Abstract:

The invention relates generally to treatment of solid cancers. More
particularly, a method and apparatus for efficient radiation dose
delivery to a tumor is described. Preferably, radiation is delivered
through an entry point into the tumor and Bragg peak energy is targeted
to a distal or far side of the tumor from an ingress point. Delivering
Bragg peak energy to the distal side of the tumor from the ingress point
is repeated from multiple rotational directions. Beam intensity is
proportional to radiation dose delivery efficiency. The multi-field
irradiation process with energy levels targeting the far side of the
tumor from each irradiation direction provides even and efficient charged
particle radiation dose delivery to the tumor. Preferably, the charged
particle therapy is timed to patient respiration via control of charged
particle beam injection, acceleration, extraction, and/or targeting
methods and apparatus.

Claims:

1. An apparatus for irradiating a tumor of a patient with charged
particles, comprising:a charged particle therapy system, comprising:a
synchrotron;a charged particle beam path; anda rotatable platform,wherein
said charged particle beam path runs through said synchrotron and above a
portion of said rotatable platform;wherein said rotatable platform
rotates at least ninety degrees during an irradiation period,wherein said
rotatable platform rotates to at least five irradiation positions during
said irradiation period.

2. The apparatus of claim 1, wherein said rotatable platform holds the
patient during said irradiation period, wherein the charged particle beam
path circumferentially surrounds the charged particles, and wherein the
charged particles irradiate the tumor during each of said at least five
irradiation positions.

3. The apparatus of claim 1, wherein said rotatable platform rotates
through about three hundred sixty degrees during said irradiation period.

4. The apparatus of claim 3, said charged particle therapy system further
comprising:an irradiation control module, wherein the tumor comprises a
distal region, said distal region furthest from point of entry of the
charged particles into the patient, wherein said irradiation control
module terminates said charged particle beam path in said distal region
of the tumor for each of said at least five irradiation positions.

5. The apparatus of claim 4, wherein said irradiation control module
controls both rotation of said rotatable platform and energy of the
charged particles to irradiate, with Bragg peak energy of the charged
particles, a changing distal position of the tumor as a function of
position of said rotatable platform.

6. The apparatus of claim 4, wherein said irradiation control module
controls energy of the charged particles to maximize charged particle
delivery efficiency of charged particle delivery of the tumor, wherein
said charged particle delivery efficiency comprises a measure of charged
particle energy delivered to the tumor relative to charged particle
energy delivered to healthy tissue.

7. The apparatus of claim 1, said charged particle therapy system further
comprising:a control module, said control module distributing distal
energy of the charged particles about an outer perimeter of the tumor,
wherein ingress energy of the charged particles comprises circumferential
distribution about the tumor.

8. The apparatus of claim 1, further comprising a control algorithm, said
control algorithm controlling both energy and intensity of the charged
particles during an extraction phase of the charged particles from said
synchrotron.

10. The apparatus of claim 9, further comprising:an extraction foil, said
extraction foil proximate said charged particle beam path in said
synchrotron, wherein during extraction the charged particles strike said
extraction foil generating a current, said current used in controlling
said intensity.

11. The apparatus of claim 1, wherein a first intensity of the charged
particles is used when energy levels of the charged particles reach a
distal region of the tumor during each of said at least five irradiation
positions, wherein a second intensity of the charged particles is used
when energy levels of the charged particles reach an ingress region of
the tumor during said each of said at least five irradiation positions,
wherein said first intensity is greater than said second intensity.

12. The apparatus of claim 1, wherein intensity of the charged particles
and energy of the charged particles correlate with a correlation factor
of at least 0.5.

13. The apparatus of claim 1, said charged particle therapy system further
comprising:a control module, wherein for at least three of said at least
five irradiation positions said control module increases intensity of the
charged particles as energy of the charged particles increases.

14. The apparatus of claim 1, wherein said rotatable platform rotates
through about three hundred sixty degrees during said irradiation period,
wherein irradiation of the tumor occurs with the charged particles in at
least thirty rotation positions of said rotatable platform during said
irradiation period.

15. The apparatus of claim 1, wherein said charged particle therapy system
further comprises:an active scanning system scanning the charged
particles along at least three axes, said active scanning system
comprising a focal spot of the charged particles of less than three
millimeters diameter, wherein said three axes comprise: a horizontal
axis, a vertical axis, and an applied energy axis.

16. The apparatus of claim 15, wherein said rotatable platform rotates to
a new position of said at least five irradiation positions between
movement of said focal spot by said active scanning system.

17. A method for irradiating a tumor of a patient with charged particles,
comprising:delivering the charged particles with a charged particle
therapy system, comprising:a synchrotron;a charged particle beam path;
anda rotatable platform, wherein said charged particle beam path runs
through said synchrotron and runs above said rotatable platform;during an
irradiation period, rotating said rotatable platform to at least five
irradiation positions coving at least ninety degrees of rotation of said
rotatable platform; andirradiating the tumor with the charged particles
during each of said at least five irradiation positions.

18. The method of claim 17, further comprising the steps of:rotating said
rotatable platform through about three hundred sixty degrees during said
irradiation period,wherein said charged particle therapy system further
comprises an irradiation control module, wherein the tumor comprises a
distal region, wherein said irradiation control module further comprises
the steps of:terminating said charged particle beam path in said distal
region of the tumor, using control of energy of the charged particles, in
each of said at least five irradiation positions; andsaid irradiation
control module controlling both rotation of said rotatable platform and
said energy of the charged particles to irradiate, with Bragg peak energy
of the charged particles, a changing distal position of the tumor as a
function of position of said rotatable platform.

20. The method of claim 17, wherein said charged particle therapy system
further comprises the step of:actively scanning the charged particles
along at least three axes, wherein said at least three axes comprise: a
horizontal axis, a vertical axis, and an applied energy axis.

[0039]Proton therapy systems typically include: a beam generator, an
accelerator, and a beam transport system to move the resulting
accelerated protons to a plurality of treatment rooms where the protons
are delivered to a tumor in a patient's body.

[0040]Proton therapy works by aiming energetic ionizing particles, such as
protons accelerated with a particle accelerator, onto a target tumor.
These particles damage the DNA of cells, ultimately causing their death.
Cancerous cells, because of their high rate of division and their reduced
ability to repair damaged DNA, are particularly vulnerable to attack on
their DNA.

[0041]Due to their relatively enormous size, protons scatter less easily
than X-rays or gamma rays in the tissue and there is very little lateral
dispersion. Hence, the proton beam stays focused on the tumor shape
without much lateral damage to surrounding tissue. All protons of a given
energy have a certain range, defined by the Bragg peak, and the dosage
delivery to tissue ratio is maximum over just the last few millimeters of
the particle's range. The penetration depth depends on the energy of the
particles, which is directly related to the speed to which the particles
were accelerated by the proton accelerator. The speed of the proton is
adjustable to the maximum rating of the accelerator. It is therefore
possible to focus the cell damage due to the proton beam at the very
depth in the tissues where the tumor is situated. Tissues situated before
the Bragg peak receive some reduced dose and tissues situated after the
peak receive none.

Problem

[0042]There exists in the art of charged particle irratiation therapy a
need for efficient, even, accurate, and precise delivery of Bragg profile
energy to a tumor. More particularly, there exists a need to deliver an
effective and uniform radiation dose to all positions of a tumor while
minimizing radiation dosage to surrounding tissue. Still further, there
exists a need in the art to control the charged particle cancer therapy
system in terms of patient translation position, patient rotation
position, specified energy, specified intensity, and/or timing of charged
particle delivery relative to a patient position. Preferably, the system
would operate in conjunction with a negative ion beam source,
synchrotron, and/or targeting method apparatus.

[0082]The invention relates generally to treatment of solid cancers. More
particularly, a method and apparatus for efficient radiation dose
delivery to a tumor is described. Preferably, radiation is delivered
through an entry point into the tumor and Bragg peak energy is targeted
to a distal or far side of the tumor from an ingress point. Delivering
Bragg peak energy to the distal side of the tumor from the ingress point
is repeated from multiple rotational directions. Beam intensity is
proportional to radiation dose delivery efficiency. The multi-field
irradiation process with energy levels targeting the far side of the
tumor from each irradiation direction provides even and efficient charged
particle radiation dose delivery to the tumor. Preferably, the charged
particle therapy is timed to patient respiration via control of charged
particle beam injection, acceleration, extraction, and/or targeting
methods and apparatus.

[0083]In one embodiment, a multi-field charged particle cancer therapy
method and apparatus with energy levels delivering radiation to the far
side of the tumor is coordinated with patient respiration via use of
feedback sensors used to monitor and/or control patient respiration.
Preferably, the charged particle therapy is performed on a patient in a
partially immobilized and repositionable position and proton delivery is
timed to patient respiration via control of charged particle beam
injection, acceleration, extraction, and/or targeting methods and
apparatus.

[0084]Used in combination with the invention, novel design features of a
charged particle beam cancer therapy system are described. Particularly,
a negative ion beam source with novel features in the negative ion
source, ion source vacuum system, ion beam focusing lens, and tandem
accelerator is described. Additionally, the synchrotron includes: turning
magnets, edge focusing magnets, magnetic field concentration magnets,
winding and correction coils, flat magnetic field incident surfaces, and
extraction elements, which minimize the overall size of the synchrotron,
provide a tightly controlled proton beam, directly reduce the size of
required magnetic fields, directly reduce required operating power, and
allow continual acceleration of protons in a synchrotron even during a
process of extracting protons from the synchrotron. The ion beam source
system and synchrotron are preferably computer integrated with a patient
imagnig system and a patient interface including respiration monitoring
sensors and patient positioning elements. Further, the system is
integrated with intensity control of a charged particle beam,
acceleration, extraction, and/or targeting method and apparatus. More
particularly, intensity, energy, and timing control of a charged particle
stream of a synchrotron is coordinated with patient positioning and tumor
treatment. The synchrotron control elements allow tight control of the
charged particle beam, which compliments the tight control of patient
positioning to yield efficient treatment of a solid tumor with reduced
tissue damage to surrounding healthy tissue. In addition, the system
reduces the overall size of the synchrotron, provides a tightly
controlled proton beam, directly reduces the size of required magnetic
fields, directly reduces required operating power, and allows continual
acceleration of protons in a synchrotron even during a process of
extracting protons from the synchrotron. All of these systems are
preferably used in conjunction with an X-ray system capable of collecting
X-rays of a patient: (1) in a positioning, immobilization, and automated
repositioning system for proton treatment; (2) at a specified moment of
the patient's respiration cycle; and (3) using coordinated translation
and rotation of the patient. Combined, the systems provide for efficient,
accurate, and precise noninvasive tumor treatment with minimal damage to
surrounding healthy tissue.

[0120]Throughout this document, a charged particle beam therapy system,
such as a proton beam, hydrogen ion beam, or carbon ion beam, is
described. Herein, the charged particle beam therapy system is described
using a proton beam. However, the aspects taught and described in terms
of a proton beam are not intended to be limiting to that of a proton beam
and are illustrative of a charged particle beam system. Any of the
techniques described herein are equally applicable to any charged
particle beam system.

[0121]Referring now to FIG. 1, a charged particle beam system 100 is
illustrated. The charged particle beam preferably comprises a number of
subsystems including any of: a main controller 110; an injection system
120; a synchrotron 130 that typically includes: (1) an accelerator system
132 and (2) an extraction system 134; a scanning/targeting/delivery
system 140; a patient interface module 150; a display system 160; and/or
an imaging system 170.

[0122]An exemplary method of use of the charged particle beam system 100
is provided. The main controller 110 controls one or more of the
subsystems to accurately and precisely deliver protons to a tumor of a
patient. For example, the main controller 110 obtains an image, such as a
portion of a body and/or of a tumor, from the imaging system 170. The
main controller 110 also obtains position and/or timing information from
the patient interface module 150. The main controller 110 then optionally
controls the injection system 120 to inject a proton into a synchrotron
130. The synchrotron typically contains at least an accelerator system
132 and an extraction system 134. The main controller preferably controls
the proton beam within the accelerator system, such as by controlling
speed, trajectory, and timing of the proton beam. The main controller
then controls extraction of a proton beam from the accelerator through
the extraction system 134. For example, the controller controls timing,
energy, and/or intensity of the extracted beam. The controller 110 also
preferably controls targeting of the proton beam through the
scanning/targeting/delivery system 140 to the patient interface module
150. One or more components of the patient interface module 150, such as
translational and rotational position of the patient, are preferably
controlled by the main controller 110. Further, display elements of the
display system 160 are preferably controlled via the main controller 110.
Displays, such as display screens, are typically provided to one or more
operators and/or to one or more patients. In one embodiment, the main
controller 110 times the delivery of the proton beam from all systems,
such that protons are delivered in an optimal therapeutic manner to the
tumor of the patient.

[0123]Herein, the main controller 110 refers to a single system
controlling the charged particle beam system 100, to a single controller
controlling a plurality of subsystems controlling the charged particle
beam system 100, or to a plurality of individual controllers controlling
one or more sub-systems of the charged particle beam system 100.

[0124]Referring now to FIG. 2, an illustrative exemplary embodiment of one
version of the charged particle beam system 100 is provided. The number,
position, and described type of components is illustrative and
non-limiting in nature. In the illustrated embodiment, the injection
system 120 or ion source or charged particle beam source generates
protons. The protons are delivered into a vacuum tube that runs into,
through, and out of the synchrotron. The generated protons are delivered
along an initial path 262. Focusing magnets 230, such as quadrupole
magnets or injection quadrupole magnets, are used to focus the proton
beam path. A quadrupole magnet is a focusing magnet. An injector bending
magnet 232 bends the proton beam toward the plane of the synchrotron 130.
The focused protons having an initial energy are introduced into an
injector magnet 240, which is preferably an injection Lamberson magnet.
Typically, the initial beam path 262 is along an axis off of, such as
above, a circulating plane of the synchrotron 130. The injector bending
magnet 232 and injector magnet 240 combine to move the protons into the
synchrotron 130. Main bending magnets, dipole magnets, or circulating
magnets 250 are used to turn the protons along a circulating beam path
264. A dipole magnet is a bending magnet. The main bending magnets 250
bend the initial beam path 262 into a circulating beam path 264. In this
example, the main bending magnets 250 or circulating magnets are
represented as four sets of four magnets to maintain the circulating beam
path 264 into a stable circulating beam path. However, any number of
magnets or sets of magnets are optionally used to move the protons around
a single orbit in the circulation process. The protons pass through an
accelerator 270. The accelerator accelerates the protons in the
circulating beam path 264. As the protons are accelerated, the fields
applied by the magnets are increased. Particularly, the speed of the
protons achieved by the accelerator 270 are synchronized with magnetic
fields of the main bending magnets 250 or circulating magnets to maintain
stable circulation of the protons about a central point or region 280 of
the synchrotron. At separate points in time the accelerator 270/main
bending magnet 250 combination is used to accelerate and/or decelerate
the circulating protons while maintaining the protons in the circulating
path or orbit. An extraction element of the inflector/deflector system
290 is used in combination with a Lamberson extraction magnet 292 to
remove protons from their circulating beam path 264 within the
synchrotron 130. One example of a deflector component is a Lamberson
magnet. Typically the deflector moves the protons from the circulating
plane to an axis off of the circulating plane, such as above the
circulating plane. Extracted protons are preferably directed and/or
focused using an extraction bending magnet 237 and extraction focusing
magnets 235, such as quadrupole magnets along a transport path 268 into
the scanning/targeting/delivery system 140. Two components of a scanning
system 140 or targeting system typically include a first axis control
142, such as a vertical control, and a second axis control 144, such as a
horizontal control. In one embodiment, the first axis control 142 allows
for about 100 mm of vertical or y-axis scanning of the proton beam 268
and the second axis control 144 allows for about 700 mm of horizontal or
x-axis scanning of the proton beam 268. A nozzle system 146 is used for
imaging the proton beam and/or as a vacuum barrier between the low
pressure beam path of the synchrotron and the atmosphere. Protons are
delivered with control to the patient interface module 150 and to a tumor
of a patient. All of the above listed elements are optional and may be
used in various permutations and combinations. Each of the above listed
elements are further described, infra.

Ion Beam Generation System

[0125]An ion beam generation system generates a negative ion beam, such as
a hydrogen anion or H.sup.- beam; preferably focuses the negative ion
beam; converts the negative ion beam to a positive ion beam, such as a
proton or H.sup.+ beam; and injects the positive ion beam 262 into the
synchrotron 130. Portions of the ion beam path are preferably under
partial vacuum. Each of these systems are further described, infra.

[0126]Referring now to FIG. 3, an exemplary ion beam generation system 300
is illustrated. As illustrated, the ion beam generation system 300 has
four major subsections: a negative ion source 310, a first partial vacuum
system 330, an optional ion beam focusing system 350, and a tandem
accelerator 390.

[0127]Still referring to FIG. 3, the negative ion source 310 preferably
includes an inlet port 312 for injection of hydrogen gas into a high
temperature plasma chamber 314. In one embodiment, the plasma chamber
includes a magnetic material 316, which provides a magnetic field 317
between the high temperature plasma chamber 314 and a low temperature
plasma region on the opposite side of the magnetic field barrier. An
extraction pulse is applied to a negative ion extraction electrode 318 to
pull the negative ion beam into a negative ion beam path 319, which
proceeds through the first partial vacuum system 330, through the ion
beam focusing system 350, and into the tandem accelerator 390.

[0128]Still referring to FIG. 3, the first partial vacuum system 330 is an
enclosed system running from the hydrogen gas inlet port 312 to a foil
395 in the tandem accelerator 390. The foil 395 is preferably sealed
directly or indirectly to the edges of the vacuum tube 320 providing for
a higher pressure, such as about 10-5 torr, to be maintained on the
first partial vacuum system 330 side of the foil 395 and a lower
pressure, such as about 10-7 torr, to be maintained on the
synchrotron side of the foil 390. By only pumping first partial vacuum
system 330 and by only semi-continuously operating the ion beam source
vacuum based on sensor readings, the lifetime of the semi-continuously
operating pump is extended. The sensor readings are further described,
infra.

[0129]Still referring to FIG. 3, the first partial vacuum system 330
preferably includes: a first pump 332, such as a continuously operating
pump and/or a turbo molecular pump; a large holding volume 334; and a
semi-continuously operating pump 336. Preferably, a pump controller 340
receives a signal from a pressure sensor 342 monitoring pressure in the
large holding volume 334. Upon a signal representative of a sufficient
pressure in the large holding volume 334, the pump controller 340
instructs an actuator 345 to open a valve 346 between the large holding
volume and the semi-continuously operating pump 336 and instructs the
semi-continuously operating pump to turn on and pump to atmosphere
residual gases out of the vacuum line 320 about the charged particle
stream. In this fashion, the lifetime of the semi-continuously operating
pump is extended by only operating semi-continuously and as needed. In
one example, the semi-continuously operating pump 336 operates for a few
minutes every few hours, such as 5 minutes every 4 hours, thereby
extending a pump with a lifetime of about 2,000 hours to about 96,000
hours.

[0130]Further, by isolating the inlet gas from the synchrotron vacuum
system, the synchrotron vacuum pumps, such as turbo molecular pumps can
operate over a longer lifetime as the synchrotron vacuum pumps have fewer
gas molecules to deal with. For example, the inlet gas is primarily
hydrogen gas but may contain impurities, such as nitrogen and carbon
dioxide. By isolating the inlet gases in the negative ion source system
310, first partial vacuum system 330, ion beam focusing system 350, and
negative ion beam side of the tandem accelerator 390, the synchrotron
vacuum pumps can operate at lower pressures with longer lifetimes, which
increases operating efficiency of the synchrotron 130.

[0131]Still referring to FIG. 3, the optimal ion beam focusing system 350
preferably includes two or more electrodes where one electrode of each
electrode pair partially obstructs the ion beam path with conductive
paths 372, such as a conductive mesh. In the illustrated example, two ion
beam focusing system sections are illustrated, a two electrode ion beam
focusing section 360 and a three electrode ion beam focusing section 370.
For a given electrode pair, electric field lines, running between the
conductive mesh of a first electrode and a second electrode, provide
inward forces focusing the negative ion beam. Multiple such electrode
pairs provide multiple negative ion beam focusing regions. Preferably the
two electrode ion focusing section 360, electrode ion focusing section
370, and second three electrode ion focusing section are placed after the
negative ion source and before the tandem accelerator and/or cover a
space of about 0.5, 1, or 2 meters along the ion beam path 319. Ion beam
focusing systems are further described, infra.

[0132]Still referring to FIG. 3, the tandem accelerator 390 preferably
includes a foil 395, such as a carbon foil. The negative ions in the
negative ion beam path 319 are converted to positive ions, such as
protons, and the initial ion beam path 262 results. The foil 395 is
preferably sealed directly or indirectly to the edges of the vacuum tube
320 providing for a higher pressure, such as about 10-5 torr, to be
maintained on the side of the foil 395 having the negative ion beam path
319 and a lower pressure, such as about 10-7 torr, to be maintained
on the side of the foil 390 having the proton ion beam path 262. Having
the foil 395 physically separating the vacuum chamber 320 into two
pressure regions allows for a system having fewer and/or smaller pumps to
maintain the lower pressure system in the synchrotron 130 as the inlet
hydrogen and its residuals are extracted in a separate contained and
isolated space by the first partial vacuum system 330.

Negative Ion Source

[0133]An example of the negative ion source 310 is further described
herein. Referring now to FIG. 4, a cross-section of an exemplary negative
ion source system 400 is provided. The negative ion beam 319 is created
in multiple stages. During a first stage, hydrogen gas is injected into a
chamber. During a second stage, a negative ion is created by application
of a first high voltage pulse, which creates a plasma about the hydrogen
gas to create negative ions. During a third stage, a magnetic field
filter is applied to components of the plasma. During a fourth stage, the
negative ions are extracted from a low temperature plasma region, on the
opposite side of the magnetic field barrier, by application of a second
high voltage pulse. Each of the four stages are further described, infra.
While the chamber is illustrated as a cross-section of a cylinder, the
cylinder is exemplary only and any geometry applies to the magnetic loop
containment walls, described infra.

[0134]In the first stage, hydrogen gas 440 is injected through the inlet
port 312 into a high temperature plasma region 490. The injection port
312 is open for a short period of time, such as less than about 1, 5, or
10 microseconds to minimize vacuum pump requirements to maintain vacuum
chamber 320 requirements. The high temperature plasma region is
maintained at reduced pressure by the partial vacuum system 330. The
injection of the hydrogen gas is optionally controlled by the main
controller 110, which is responsive to imaging system 170 information and
patient interface module 150 information, such as patient positioning and
period in a respiration cycle.

[0135]In the second stage, a high temperature plasma region is created by
applying a first high voltage pulse across a first electrode 422 and a
second electrode 424. For example a 5 kV pulse is applied for about 20
microseconds with 5 kV at the second electrode 424 and about 0 kV applied
at the first electrode 422. Hydrogen in the chamber is broken, in the
high temperature plasma region 490, into component parts, such as any of:
atomic hydrogen, H0, a proton, H.sup.+, an electron, e.sup.-, and a
hydrogen anion, H.sup.-.

[0136]In the third stage, the high temperature plasma region 490 is at
least partially separated from a low temperature plasma region 492 by the
magnetic field 317 or in this specific example a magnetic field barrier
430. High energy electrons are restricted from passing through the
magnetic field barrier 430. In this manner, the magnetic field barrier
430 acts as a filter between, zone A and zone B, in the negative ion
source. Preferably, a central magnetic material 410, which is an example
of the magnetic material 316, is placed within the high temperature
plasma region 490, such as along a central axis of the high temperature
plasma region 490. Preferably, the first electrode 422 and second
electrode 424 are composed of magnetic materials, such as iron.
Preferably, the outer walls 450 of the high temperature plasma region,
such as cylinder walls, are composed of a magnetic material, such as a
permanent magnet, ferric or iron based material, or a ferrite dielectric
ring magnet. In this manner a magnetic field loop is created by: the
central magnetic material 410, first electrode 422, the outer walls 450,
the second electrode 424, and the magnetic field barrier 430. Again, the
magnetic field barrier 430 restricts high energy electrons from passing
through the magnetic field barrier 430. Low energy electrons interact
with atomic hydrogen, H0, to create a hydrogen anion, H.sup.-, in
the low temperature plasma region 492.

[0137]In the fourth stage, a second high voltage pulse or extraction pulse
is applied at a third electrode 426. The second high voltage pulse is
preferentially applied during the later period of application of the
first high voltage pulse. For example, an extraction pulse of about 25 kV
is applied for about the last 5 microseconds of the first creation pulse
of about 20 microseconds. The potential difference, of about 20 kV,
between the third electrode 426 and second electrode 424 extracts the
negative ion, H.sup.-, from the low temperature plasma region 492 and
initiates the negative ion beam 319, from zone B to zone C.

[0138]The magnetic field barrier 430 is optionally created in number of
ways. An example of creation of the magnetic field barrier 430 using
coils is provided. In this example, the elements described, supra, in
relation to FIG. 4 are maintained with several differences. First, the
magnetic field is created using coils. An isolating material is
preferably provided between the first electrode 422 and the cylinder
walls 450 as well as between the second electrode 424 and the cylinder
walls 450. The central material 410 and/or cylinder walls 450 are
optionally metallic. In this manner, the coils create a magnetic field
loop through the first electrode 422, isolating material, outer walls
450, second electrode 424, magnetic field barrier 430, and the central
material 410. Essentially, the coils generate a magnetic field in place
of production of the magnetic field by the magnetic material 410. The
magnetic field barrier 430 operates as described, supra. Generally, any
manner that creates the magnetic field barrier 430 between the high
temperature plasma region 490 and low temperature plasma region 492 is
functionally applicable to the ion beam extraction system 400, described
herein.

Ion Beam Focusing System

[0139]Referring now to FIG. 5, the ion beam focusing system 350 is further
described. In this example, three electrodes are used. In this example, a
first electrode 510 and third electrode 530 are both negatively charged
and each is a ring electrode circumferentially enclosing or at least
partially enclosing the negative ion beam path 319. A second electrode
520 is positively charged and is also a ring electrode at least partially
and preferably substantially circumferentially enclosing the negative ion
beam path. In addition, the second electrode includes one or more
conducting paths 372 running through the negative ion beam path 319. For
example, the conducting paths are a wire mesh, a conducting grid, or a
series of substantially parallel conducting lines running across the
second electrode. In use, electric field lines run from the conducting
paths of the positively charged electrode to the negatively charged
electrodes. For example, in use the electric field lines 540 run from the
conducting paths 372 in the negative ion beam path 319 to the negatively
charged electrodes 510, 530. Two ray trace lines 550, 560 of the negative
ion beam path are used to illustrate focusing forces. In the first ray
trace line 550, the negative ion beam encounters a first electric field
line at point M. Negatively charged ions in the negative ion beam 550
encounter forces running up the electric field line 572, illustrated with
an x-axis component vector 571. The x-axis component force vectors 571
alters the trajectory of the first ray trace line to a inward focused
vector 552, which encounters a second electric field line at point N.
Again, the negative ion beam 552 encounters forces running up the
electric field line 574, illustrated as having an inward force vector
with an x-axis component 573, which alters the inward focused vector 552
to a more inward focused vector 554. Similarly, in the second ray trace
line 560, the negative ion beam encounters a first electric field line at
point O. Negatively charged ions in the negative ion beam encounter
forces running up the electric field line 576, illustrated as having a
force vector with an x-axis force 575. The inward force vector 575 alters
the trajectory of the second ray trace line 560 to an inward focused
vector 562, which encounters a second electric field line at point P.
Again, the negative ion beam encounters forces running up the electric
field line 578, illustrated as having force vector with an x-axis
component 577, which alters the inward focused vector 562 to a more
inward focused vector 564. The net result is a focusing effect on the
negative ion beam. Each of the force vectors 572, 574, 576, 578
optionally has x and/or y force vector components resulting in a
3-dimensional focusing of the negative ion beam path. Naturally, the
force vectors are illustrative in nature, many electric field lines are
encountered, and the focusing effect is observed at each encounter
resulting in integral focusing. The example is used to illustrate the
focusing effect.

[0140]Still referring to FIG. 5, optionally any number of electrodes are
used, such as 2, 3, 4, 5, 6, 7, 8, or 9 electrodes, to focus the negative
ion beam path where every other electrode, in a given focusing section,
is either positively or negatively charged. For example, three focusing
sections are optionally used. In the first ion focusing section 360, a
pair of electrodes is used where the first electrode encountered along
the negative ion beam path is negatively charged and the second electrode
is positively charged, resulting in focusing of the negative ion beam
path. In the second ion focusing section 370, two pairs of electrodes are
used, where a common positively charged electrode with a conductive mesh
running through the negatively ion beam path 319 is used. Thus, in the
second ion focusing section 370, the first electrode encountered along
the negative ion beam path is negatively charged and the second electrode
is positively charged, resulting in focusing of the negative ion beam
path. Further, in the second ion focusing section, moving along the
negative ion beam path, a second focusing effect is observed between the
second positively charged electrode and a third negatively charged
electrode. In this example, a third ion focusing section is used that
again has three electrodes, which acts in the fashion of the second ion
focusing section, describe supra.

[0141]Referring now to FIG. 6, the central region of the electrodes in the
ion beam focusing system 350 are further described. Referring now to FIG.
6A, the central region of the negatively charged ring electrode 510 is
preferably void of conductive material. Referring now to FIGS. 6B-D, the
central region of positively charged electrode ring 520 preferably
contains conductive paths 372. Preferably, the conductive paths 372 or
conductive material within the positively charged electrode ring 520
blocks about 1, 2, 5, or 10 percent of the area and more preferably
blocks about 5 percent of the cross-sectional area of the negative ion
beam path 319. Referring now to FIG. 6B, one option is a conductive mesh
610. Referring now to FIG. 6c, a second option is a series of conductive
lines 620 running substantially in parallel across the positively charged
electrode ring 520 that surrounds a portion of the negative ion beam path
319. Referring now to FIG. 6D, a third option is to have a foil 630 or
metallic layer cover all of the cross-sectional area of the negative ion
beam path with holes punched through the material, where the holes take
up about 90-99 percent and more preferably about 95 percent of the area
of the foil. More generally, the pair of electrodes 510, 520 are
configured to provide electric field lines that provide focusing force
vectors to the negative ion beam 319 when the ions in the negative ion
beam 319 translate through the electric field lines, as described supra.

[0142]In an example of a two electrode negative beam ion focusing system
having a first cross-sectional diameter, d1, the negative ions are
focused to a second cross-sectional diameter, d2, where
d1>d2. Similarly, in an example of a three electrode
negative beam ion focusing system having a first ion beam cross-sectional
diameter, d1, the negative ions are focused using the three
electrode system to a third negative ion beam cross-sectional diameter,
d3, where d1>d3. For like potentials on the electrodes,
the three electrode system provides tighter or stronger focusing compared
to the two-electrode system, d3<d2.

[0143]In the examples provided, supra, of a multi-electrode ion beam
focusing system, the electrodes are rings. More generally, the electrodes
are of any geometry sufficient to provide electric field lines that
provide focusing force vectors to the negative ion beam when the ions in
the negative ion beam 319 translate through the electric field lines, as
described supra. For example, one negative ring electrode is optionally
replaced by a number of negatively charged electrodes, such as about 2,
3, 4, 6, 8, 10, or more electrodes placed about the outer region of a
cross-sectional area of the negative ion beam probe. Generally, more
electrodes are required to converge or diverge a faster or higher energy
beam.

[0144]In another embodiment, by reversing the polarity of electrodes in
the above example, the negative ion beam is made to diverge. Thus, the
negative ion beam path 319 is optionally focused and/or expanded using
combinations of electrode pairs. For example, if the electrode having the
mesh across the negative ion beam path is made negative, then the
negative ion beam path is made to defocus. Hence, combinations of
electrode pairs are used for focusing and defocusing a negative ion beam
path, such as where a first pair includes a positively charged mesh for
focusing and a where a second pair includes a negatively charged mesh for
defocusing.

Tandem Accelerator

[0145]Referring now to FIG. 7A, the tandem accelerator 390 is further
described. The tandem accelerator accelerates ions using a series of
electrodes 710, 711, 712, 713, 714, 715. For example, negative ions, such
as H.sup.-, in the negative ion beam path are accelerated using a series
of electrodes having progressively higher voltages relative to the
voltage of the extraction electrode 426, or third electrode 426, of the
negative ion beam source 310. For instance, the tandem accelerator 390
optionally has electrodes ranging from the 25 kV of the extraction
electrode 426 to about 525 kV near the foil 395 in the tandem accelerator
390. Upon passing through the foil 395, the negative ion, H.sup.-, loses
two electrons to yield a proton, H.sup.+, according to equation 1.

H.sup.-→H.sup.++2e.sup.- (eq. 1)

[0146]The proton is further accelerated in the tandem accelerator using
appropriate voltages at a multitude of further electrodes 713, 714, 715.
The protons are then injected into the synchrotron 130 as described,
supra.

[0147]Still referring to FIG. 7, the foil 395 in the tandem accelerator
390 is further described. The foil 395 is preferably a very thin carbon
film of about 30 to 200 angstroms in thickness. The foil thickness is
designed to both: (1) not block the ion beam and (2) allow the transfer
of electrons yielding protons to form the proton beam path 262. The foil
395 is preferably substantially in contact with a support layer 720, such
as a support grid. The support layer 720 provides mechanical strength to
the foil 395 to combine to form a vacuum blocking element 725. The foil
395 blocks nitrogen, carbon dioxide, hydrogen, and other gases from
passing and thus acts as a vacuum barrier. In one embodiment, the foil
395 is preferably sealed directly or indirectly to the edges of the
vacuum tube 320 providing for a higher pressure, such as about 10-5
torr, to be maintained on the side of the foil 395 having the negative
ion beam path 319 and a lower pressure, such as about 10-7 torr, to
be maintained on the side of the foil 395 having the proton ion beam path
262. Having the foil 395 physically separating the vacuum chamber 320
into two pressure regions allows for a vacuum system having fewer and/or
smaller pumps to maintain the lower pressure system in the synchrotron
130 as the inlet hydrogen and its residuals are extracted in a separate
contained and isolated space by the first partial vacuum system 330. The
foil 395 and support layer 720 are preferably attached to the structure
750 of the tandem accelerator 390 or vacuum tube 320 to form a pressure
barrier using any mechanical means, such as a metal, plastic, or ceramic
ring 730 compressed to the walls with an attachment screw 740. Any
mechanical means for separating and sealing the two vacuum chamber sides
with the foil 395 are equally applicable to this system. Referring now to
FIG. 7B, the support structure 720 and foil 395 are individually viewed
in the x-, y-plane.

[0148]Referring now to FIG. 8, another exemplary method of use of the
charged particle beam system 100 is provided. The main controller 110, or
one or more sub-controllers, controls one or more of the subsystems to
accurately and precisely deliver protons to a tumor of a patient. For
example, the main controller sends a message to the patient indicating
when or how to breath. The main controller 110 obtains a sensor reading
from the patient interface module, such as a temperature breath sensor or
a force reading indicative of where in a respiration cycle the subject
is. Coordinated at a specific and reproducible point in the respiration
cycle, the main controller collects an image, such as a portion of a body
and/or of a tumor, from the imaging system 170. The main controller 110
also obtains position and/or timing information from the patient
interface module 150. The main controller 110 then optionally controls
the injection system 120 to inject hydrogen gas into a negative ion beam
source 310 and controls timing of extraction of the negative ion from the
negative ion beam source 310. Optionally, the main controller controls
ion beam focusing the ion beam focusing lens system 350; acceleration of
the proton beam with the tandem accelerator 390; and/or injection of the
proton into the synchrotron 130. The synchrotron typically contains at
least an accelerator system 132 and an extraction system 134. The
synchrotron preferably contains one or more of: turning magnets, edge
focusing magnets, magnetic field concentration magnets, winding and
correction coils, and flat magnetic field incident surfaces, some of
which contain elements under control by the main controller 110. The main
controller preferably controls the proton beam within the accelerator
system, such as by controlling speed, trajectory, and/or timing of the
proton beam. The main controller then controls extraction of a proton
beam from the accelerator through the extraction system 134. For example,
the controller controls timing, energy, and/or intensity of the extracted
beam. The main controller 110 also preferably controls targeting of the
proton beam through the targeting/delivery system 140 to the patient
interface module 150. One or more components of the patient interface
module 150 are preferably controlled by the main controller 110, such as
vertical position of the patient, rotational position of the patient, and
patient chair positioning/stabilization/immobilization/control elements.
Further, display elements of the display system 160 are preferably
controlled via the main controller 110. Displays, such as display
screens, are typically provided to one or more operators and/or to one or
more patients. In one embodiment, the main controller 110 times the
delivery of the proton beam from all systems, such that protons are
delivered in an optimal therapeutic manner to the tumor of the patient.

Synchrotron

[0149]Herein, the term synchrotron is used to refer to a system
maintaining the charged particle beam in a circulating path; however,
cyclotrons are alternatively used, albeit with their inherent limitations
of energy, intensity, and extraction control. Further, the charged
particle beam is referred to herein as circulating along a circulating
path about a central point of the synchrotron. The circulating path is
alternatively referred to as an orbiting path; however, the orbiting path
does not refer a perfect circle or ellipse, rather it refers to cycling
of the protons around a central point or region 280.

Circulating System

[0150]Referring now to FIG. 9, the synchrotron 130 preferably comprises a
combination of straight sections 910 and ion beam turning sections 920.
Hence, the circulating path of the protons is not circular in a
synchrotron, but is rather a polygon with rounded corners.

[0151]In one illustrative embodiment, the synchrotron 130, which as also
referred to as an accelerator system, has four straight elements or
sections and four turning sections. Examples of straight sections 910
include the: inflector 240, accelerator 270, extraction system 290, and
deflector 292. Along with the four straight sections are four ion beam
turning sections 920, which are also referred to as magnet sections or
turning sections. Turning sections are further described, infra.

[0152]Referring still to FIG. 9, an exemplary synchrotron is illustrated.
In this example, protons delivered along the initial proton beam path 262
are inflected into the circulating beam path with the inflector 240 and
after acceleration are extracted via a deflector 292 to the beam
transport path 268. In this example, the synchrotron 130 comprises four
straight sections 910 and four bending or turning sections 920 where each
of the four turning sections use one or more magnets to turn the proton
beam about ninety degrees. As is further described, infra, the ability to
closely space the turning sections and efficiently turn the proton beam
results in shorter straight sections. Shorter straight sections allows
for a synchrotron design without the use of focusing quadrupoles in the
circulating beam path of the synchrotron. The removal of the focusing
quadrupoles from the circulating proton beam path results in a more
compact design. In this example, the illustrated synchrotron has about a
five meter diameter versus eight meter and larger cross-sectional
diameters for systems using a quadrupole focusing magnet in the
circulating proton beam path.

[0153]Referring now to FIG. 10, additional description of the first
bending or turning section 920 is provided. Each of the turning sections
preferably comprise multiple magnets, such as about 2, 4, 6, 8, 10, or 12
magnets. In this example, four turning magnets 1010, 1020, 1030, 1040 in
the first turning section 920 are used to illustrate key principles,
which are the same regardless of the number of magnets in a turning
section 920. The turning magnets 1010, 1020, 1030, 1040 are particular
types of main bending or circulating magnets 250.

[0154]In physics, the Lorentz force is the force on a point charge due to
electromagnetic fields. The Lorentz force is given by equation 2 in terms
of magnetic fields with the election field terms not included.

F=q(v×B) (eq. 2)

[0155]In equation 2, F is the force in newtons; q is the electric charge
in coulombs; B is the magnetic field in Teslas; and v is the
instantaneous velocity of the particles in meters per second.

[0156]Referring now to FIG. 11, an example of a single magnet bending or
turning section 1010 is expanded. The turning section includes a gap 1110
through which protons circulate. The gap 1110 is preferably a flat gap,
allowing for a magnetic field across the gap 1110 that is more uniform,
even, and intense. A magnetic field enters the gap 1110 through a
magnetic field incident surface and exits the gap 1110 through a magnetic
field exiting surface. The gap 1110 runs in a vacuum tube between two
magnet halves. The gap 1110 is controlled by at least two parameters: (1)
the gap 1110 is kept as large as possible to minimize loss of protons and
(2) the gap 1110 is kept as small as possible to minimize magnet sizes
and the associated size and power requirements of the magnet power
supplies. The flat nature of the gap 1110 allows for a compressed and
more uniform magnetic field across the gap 1110. One example of a gap
dimension is to accommodate a vertical proton beam size of about two
centimeters with a horizontal beam size of about five to six centimeters.

[0157]As described, supra, a larger gap size requires a larger power
supply. For instance, if the gap 1110 size doubles in vertical size, then
the power supply requirements increase by about a factor of four. The
flatness of the gap 1110 is also important. For example, the flat nature
of the gap 1110 allows for an increase in energy of the extracted protons
from about 250 to about 330 MeV. More particularly, if the gap 1110 has
an extremely flat surface, then the limits of a magnetic field of an iron
magnet are reachable. An exemplary precision of the flat surface of the
gap 1110 is a polish of less than about 5 microns and preferably with a
polish of about 1 to 3 microns. Unevenness in the surface results in
imperfections in the applied magnetic field. The polished flat surface
spreads unevenness of the applied magnetic field.

[0158]Still referring to FIG. 11, the charged particle beam moves through
the gap 1110 with an instantaneous velocity, v. A first magnetic coil
1120 and a second magnetic coil 1130 run above and below the gap 1110,
respectively. Current running through the coils 1120, 1130 results in a
magnetic field, B, running through the single magnet turning section
1010. In this example, the magnetic field, B, runs upward, which results
in a force, F, pushing the charged particle beam inward toward a central
point of the synchrotron, which turns the charged particle beam in an
arc.

[0159]Still referring to FIG. 11, a portion of an optional second magnet
bending or turning section 1020 is illustrated. The coils 1120, 1130
typically have return elements 1140, 1150 or turns at the end of one
magnet, such as at the end of the first magnet turning section 1010. The
turns 1140, 1150 take space. The space reduces the percentage of the path
about one orbit of the synchrotron that is covered by the turning
magnets. This leads to portions of the circulating path where the protons
are not turned and/or focused and allows for portions of the circulating
path where the proton path defocuses. Thus, the space results in a larger
synchrotron. Therefore, the space between magnet turning sections 1160 is
preferably minimized. The second turning magnet is used to illustrate
that the coils 1120, 1130 optionally run along a plurality of magnets,
such as 2, 3, 4, 5, 6, or more magnets. Coils 1120, 1130 running across
multiple turning section magnets allows for two turning section magnets
to be spatially positioned closer to each other due to the removal of the
steric constraint of the turns, which reduces and/or minimizes the space
1160 between two turning section magnets.

[0160]Referring now to FIGS. 12 and 13, two illustrative 90 degree rotated
cross-sections of single magnet bending or turning sections 1010 are
presented. The magnet assembly has a first magnet 1210 and a second
magnet 1220. A magnetic field induced by coils, described infra, runs
between the first magnet 1210 to the second magnet 1220 across the gap
1110. Return magnetic fields run through a first yoke 1212 and second
yoke 1222. The combined cross-section area of the return yokes roughly
approximates the cross-sectional area of the first magnet 1210 or second
magnet 1220. The charged particles run through the vacuum tube in the gap
1110. As illustrated, protons run into FIG. 12 through the gap 1110 and
the magnetic field, illustrated as vector B, applies a force F to the
protons pushing the protons towards the center of the synchrotron, which
is off page to the right in FIG. 12. The magnetic field is created using
windings. A first coil makes up a first winding coil 1250 and a second
coil of wire makes up a second winding coil 1260. Isolating or
concentrating gaps 1230, 1240, such as air gaps, isolate the iron based
yokes from the gap 1110. The gap 1110 is approximately flat to yield a
uniform magnetic field across the gap 1110, as described supra.

[0161]Still referring to FIG. 13, the ends of a single bending or turning
magnet are preferably beveled. Nearly perpendicular or right angle edges
of a turning magnet 1010 are represented by dashed lines 1374, 1384. The
dashed lines 1374, 1384 intersect at a point 1390 beyond the center of
the synchrotron 280. Preferably, the edge of the turning magnet is
beveled at angles alpha, α, and beta, β, which are angles
formed by a first line 1372, 1382 going from an edge of the turning
magnet 1010 and the center 280 and a second line 1374, 1384 going from
the same edge of the turning magnet and the intersecting point 1390. The
angle alpha is used to describe the effect and the description of angle
alpha applies to angle beta, but angle alpha is optionally different from
angle beta. The angle alpha provides an edge focusing effect. Beveling
the edge of the turning magnet 1010 at angle alpha focuses the proton
beam.

[0162]Multiple turning magnets provide multiple magnet edges that each
have edge focusing effects in the synchrotron 130. If only one turning
magnet is used, then the beam is only focused once for angle alpha or
twice for angle alpha and angle beta. However, by using smaller turning
magnets, more turning magnets fit into the turning sections 920 of the
synchrotron 130. For example, if four magnets are used in a turning
section 920 of the synchrotron, then for a single turning section there
are eight possible edge focusing effect surfaces, two edges per magnet.
The eight focusing surfaces yield a smaller cross-sectional beam size,
which allows the use of a smaller gap.

[0163]The use of multiple edge focusing effects in the turning magnets
results in not only a smaller gap 1110, but also the use of smaller
magnets and smaller power supplies. For a synchrotron 130 having four
turning sections 920 where each turning sections has four turning magnets
and each turning magnet has two focusing edges, a total of thirty-two
focusing edges exist for each orbit of the protons in the circulating
path of the synchrotron 130. Similarly, if 2, 6, or 8 magnets are used in
a given turning section, or if 2, 3, 5, or 6 turning sections are used,
then the number of edge focusing surfaces expands or contracts according
to equation 3.

T F E = N T S * M N T S
* F E M ( eq . 3 ) ##EQU00001##

where TFE is the number of total focusing edges, NTS is the number of
turning sections, M is the number of magnets, and FE is the number of
focusing edges. Naturally, not all magnets are necessarily beveled and
some magnets are optionally beveled on only one edge.

[0164]The inventors have determined that multiple smaller magnets have
benefits over fewer larger magnets. For example, the use of 16 small
magnets yields 32 focusing edges whereas the use of 4 larger magnets
yields only 8 focusing edges. The use of a synchrotron having more
focusing edges results in a circulating path of the synchrotron built
without the use of focusing quadrupole magnets. All prior art
synchrotrons use quadrupoles in the circulating path of the synchrotron.
Further, the use of quadrupoles in the circulating path necessitates
additional straight sections in the circulating path of the synchrotron.
Thus, the use of quadrupoles in the circulating path of a synchrotron
results in synchrotrons having larger diameters, larger circulating beam
pathlengths, and/or larger circumferences.

[0165]In various embodiments of the system described herein, the
synchrotron has any combination of: [0166]at least 4 and preferably 6,
8, 10, or more edge focusing edges per 90 degrees of turn of the charged
particle beam in a synchrotron having four turning sections; [0167]at
least about 16 and preferably about 24, 32, or more edge focusing edges
per orbit of the charged particle beam in the synchrotron; [0168]only 4
turning sections where each of the turning sections includes at least 4
and preferably 8 edge focusing edges; [0169]an equal number of straight
sections and turning sections; [0170]exactly 4 turning sections; [0171]at
least 4 focusing edges per turning section; [0172]no quadrupoles in the
circulating path of the synchrotron; [0173]a rounded corner rectangular
polygon configuration; [0174]a circumference of less than 60 meters;
[0175]a circumference of less than 60 meters and 32 edge focusing
surfaces; and/or [0176]any of about 8, 16, 24, or 32 non-quadrupole
magnets per circulating path of the synchrotron, where the non-quadrupole
magnets include edge focusing edges.

Flat Gap Surface

[0177]While the gap surface is described in terms of the first turning
magnet 1010, the discussion applies to each of the turning magnets in the
synchrotron. Similarly, while the gap 1110 surface is described in terms
of the magnetic field incident surface 670, the discussion additionally
optionally applies to the magnetic field exiting surface 680.

[0178]Referring again to FIG. 12, the incident magnetic field surface 1270
of the first magnet 1210 is further described. FIG. 12 is not to scale
and is illustrative in nature. Local imperfections or unevenness in
quality of the finish of the incident surface 1270 results in
inhomogeneities or imperfections in the magnetic field applied to the gap
1110. The magnetic field incident surface 1270 and/or exiting surface
1280 of the first magnet 1210 is preferably about flat, such as to within
about a zero to three micron finish polish or less preferably to about a
ten micron finish polish. By being very flat, the polished surface
spreads the unevenness of the applied magnetic field across the gap 1110.
The very flat surface, such as about 0, 1, 2, 4, 6, 8, 10, 15, or 20
micron finish, allows for a smaller gap size, a smaller applied magnetic
field, smaller power supplies, and tighter control of the proton beam
cross-sectional area.

[0179]Referring now to FIG. 14, additional optional magnet elements, of
the magnet cross-section illustratively represented in FIG. 12, are
described. The first magnet 1210 preferably contains an initial
cross-sectional distance 1410 of the iron based core. The contours of the
magnetic field are shaped by the magnets 1210, 1220 and the yokes 1212,
1222. The iron based core tapers to a second cross-sectional distance
1420. The shape of the magnetic field vector 1440 is illustrative only.
The magnetic field in the magnet preferentially stays in the iron based
core as opposed to the gaps 1230, 1240. As the cross-sectional distance
decreases from the initial cross-sectional distance 1410 to the final
cross-sectional distance 1420, the magnetic field concentrates. The
change in shape of the magnet from the longer distance 1410 to the
smaller distance 1420 acts as an amplifier. The concentration of the
magnetic field is illustrated by representing an initial density of
magnetic field vectors 1430 in the initial cross-section 1410 to a
concentrated density of magnetic field vectors 1440 in the final
cross-section 1420. The concentration of the magnetic field due to the
geometry of the turning magnets results in fewer winding coils 1250, 1260
being required and also a smaller power supply to the coils being
required.

[0180]In one example, the initial cross-section distance 1410 is about
fifteen centimeters and the final cross-section distance 1420 is about
ten centimeters. Using the provided numbers, the concentration of the
magnetic field is about 15/10 or 1.5 times at the incident surface 1270
of the gap 1110, though the relationship is not linear. The taper 1460
has a slope, such as about 20, 40, or 60 degrees. The concentration of
the magnetic field, such as by 1.5 times, leads to a corresponding
decrease in power consumption requirements to the magnets.

[0181]Referring now to FIG. 15, an additional example of geometry of the
magnet used to concentrate the magnetic field is illustrated. As
illustrated in FIG. 14, the first magnet 1210 preferably contains an
initial cross-sectional distance 1410 of the iron based core. The
contours of the magnetic field are shaped by the magnets 1210, 1220 and
the yokes 1212, 1222. In this example, the core tapers to a second
cross-sectional distance 1420 with a smaller angle theta, θ. As
described, supra, the magnetic field in the magnet preferentially stays
in the iron based core as opposed to the gaps 1230, 1240. As the
cross-sectional distance decreases from the initial cross-sectional
distance 1410 to the final cross-sectional distance 1420, the magnetic
field concentrates. The smaller angle, theta, results in a greater
amplification of the magnetic field in going from the longer distance
1410 to the smaller distance 1420. The concentration of the magnetic
field is illustrated by representing an initial density of magnetic field
vectors 1430 in the initial cross-section 1410 to a concentrated density
of magnetic field vectors 1440 in the final cross-section 1420. The
concentration of the magnetic field due to the geometry of the turning
magnets results in fewer winding coils 1250, 1260 being required and also
a smaller power supply to the winding coils 1250, 1260 being required.

[0182]Still referring to FIG. 15, optional correction coils 1510, 1520 are
illustrated that are used to correct the strength of one or more turning
magnets. The correction coils 1520, 1530 supplement the winding coils
1250, 1260. The correction coils 1510, 1520 have correction coil power
supplies that are separate from winding coil power supplies used with the
winding coils 1250, 1260. The correction coil power supplies typically
operate at a fraction of the power required compared to the winding coil
power supplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power
and more preferably about 1 or 2 percent of the power used with the
winding coils 1250, 1260. The smaller operating power applied to the
correction coils 1510, 1520 allows for more accurate and/or precise
control of the correction coils. The correction coils are used to adjust
for imperfection in the turning magnets. Optionally, separate correction
coils are used for each turning magnet allowing individual tuning of the
magnetic field for each turning magnet, which eases quality requirements
in the manufacture of each turning magnet.

[0183]Referring now to FIG. 16, an example of winding coils 1630 and
correction coils 1620 about a plurality of turning magnets 1010, 1020 in
an ion beam turning section 920 is illustrated. As illustrated, the
winding coils preferably cover 1, 2, or 4 turning magnets. One or more
high precision magnetic field sensors 1830 are placed into the
synchrotron and are used to measure the magnetic field at or near the
proton beam path. For example, the magnetic sensors are optionally placed
between turning magnets and/or within a turning magnet, such as at or
near the gap 1110 or at or near the magnet core or yoke. The sensors are
part of a feedback system to the correction coils, which is optionally
run by the main controller. Thus, the system preferably stabilizes the
magnetic field in the synchrotron rather than stabilizing the current
applied to the magnets. Stabilization of the magnetic field allows the
synchrotron to come to a new energy level quickly. This allows the system
to be controlled to an operator or algorithm selected energy level with
each pulse of the synchrotron and/or with each breath of the patient.

[0184]The winding and/or correction coils correct 1, 2, 3, or 4 turning
magnets, and preferably correct a magnetic field generated by two turning
magnets. A winding or correction coil covering multiple magnets reduces
space between magnets as fewer winding or correction coil ends are
required, which occupy space. In the illustrated example, a correction
coil 1610 winds around a single turning magnet 1010. In another example,
a correction coil 1640 winds around two magnets. In another example, the
correction coil 1620 winds around four magnets controlled primarily by a
first winding 1630.

[0185]Space 1160 at the end of a turning magnets 1010, 1040 is optionally
further reduced by changing the cross-sectional shape of the winding
coils. For example, when the winding coils are running longitudinally
along the length of the circulating path or along the length of the
turning magnet, the cross-sectional dimension is thick and when the
winding coils turn at the end of a turning magnet to run axially across
the winding coil, then the cross-sectional area of the winding coils is
preferably thin. For example, the cross-sectional area of winding coils
as measured by an m×n matrix is 3×2 running longitudinally
along the turning magnet and 6×1 running axially at the end of the
turning magnet, thereby reducing the width of the coils, n, while keeping
the number of coils constant. Preferably, the turn from the longitudinal
to axial direction of the winding coil approximates ninety degrees by
cutting each winding and welding each longitudinal section to the
connecting axial section at about a ninety degree angle. The nearly
perpendicular weld further reduces space requirements of the turn in the
winding coil, which reduces space in circulating orbit not experiencing
focusing and turning forces, which reduces the size of the synchrotron.

[0186]Referring now to FIG. 17A and FIG. 17B, the accelerator system 270,
such as a radio-frequency (RF) accelerator system, is further described.
The accelerator includes a series of coils 1710-1719, such as iron or
ferrite coils, each circumferentially enclosing the vacuum system 320
through which the proton beam 264 passes in the synchrotron 130.
Referring now to FIG. 17B, the first coil 1710 is further described. A
loop of standard wire 1730 completes at least one turn about the first
coil 1710. The loop attaches to a microcircuit 1720. Referring again to
FIG. 17A, an RF synthesizer 1740, which is preferably connected to the
main controller 110, provides a low voltage RF signal that is
synchronized to the period of circulation of protons in the proton beam
path 264. The RF synthesizer 1740, microcircuit 1720, loop 1730, and coil
1710 combine to provide an accelerating voltage to the protons in the
proton beam path 264. For example, the RF synthesizer 1740 sends a signal
to the microcircuit 1720, which amplifies the low voltage RF signal and
yields an acceleration voltage, such as about 10 volts. The actual
acceleration voltage for a single microcircuit/loop/coil combination is
about 5, 10, 15, or 20 volts, but is preferably about 10 volts.
Preferably, the RF-amplifier microcircuit and accelerating coil are
integrated.

[0187]Still referring to FIG. 17A, the integrated RF-amplifier
microcircuit and accelerating coil presented in FIG. 17B is repeated, as
illustrated as the set of coils 1711-1719 surrounding the vacuum tube
320. For example, the RF-synthesizer 1740, under main controller 130
direction, sends an RF-signal to the microcircuits 1720-1729 connected to
coils 1710-1719, respectively. Each of the microcircuit/loop/coil
combinations generates a proton accelerating voltage, such as about 10
volts each. Hence, a set of five coil combinations generates about 50
volts for proton acceleration. Preferably about 5 to 20
microcircuit/loop/coil combinations are used and more preferably about 9
or 10 microcircuit/loop/coil combinations are used in the accelerator
system 270.

[0188]As a further clarifying example, the RF synthesizer 1740 sends an
RF-signal, with a period equal to a period of circulation of a proton
about the synchrotron 130, to a set of ten microcircuit/loop/coil
combinations, which results in about 100 volts for acceleration of the
protons in the proton beam path 264. The 100 volts is generated at a
range of frequencies, such as at about 1 MHz for a low energy proton beam
to about 15 MHz for a high energy proton beam. The RF-signal is
optionally set at an integer multiple of a period of circulation of the
proton about the synchrotron circulating path. Each of the
microcircuit/loop/coil combinations are optionally independently
controlled in terms of acceleration voltage and frequency.

[0189]Integration of the RF-amplifier microcircuit and accelerating coil,
in each microcircuit/loop/coil combination, results in three considerable
advantages. First, for synchrotrons, the prior art does not use
microcircuits integrated with the accelerating coils but rather uses a
set of long cables to provide power to a corresponding set of coils. The
long cables have an impedance/resistance, which is problematic for high
frequency RF control. As a result, the prior art system is not operable
at high frequencies, such as above about 10 MHz. The integrated
RF-amplifier microcircuit/accelerating coil system is operable at above
about 10 MHz and even 15 MHz where the impedance and/or resistance of the
long cables in the prior art systems results in poor control or failure
in proton acceleration. Second, the long cable system, operating at lower
frequencies, costs about $50,000 and the integrated microcircuit system
costs about $1000, which is 50 times less expensive. Third, the
microcircuit/loop/coil combinations in conjunction with the RF-amplifier
system results in a compact low power consumption design allowing
production and use of a proton cancer therapy system in a small space, as
described supra, and in a cost effective manner.

[0190]Referring now to FIG. 18, an example is used to clarify the magnetic
field control using a feedback loop 1800 to change delivery times and/or
periods of proton pulse delivery. In one case, a respiratory sensor 1810
senses the respiration cycle of the subject. The respiratory sensor sends
the information to an algorithm in a magnetic field controller 1820,
typically via the patient interface module 150 and/or via the main
controller 110 or a subcomponent thereof. The algorithm predicts and/or
measures when the subject is at a particular point in the respiration
cycle, such as at the bottom of a breath. Magnetic field sensors 1830 are
used as input to the magnetic field controller, which controls a magnet
power supply 1840 for a given magnetic field 1850, such as within a first
turning magnet 1010 of a synchrotron 130. The control feedback loop is
thus used to dial the synchrotron to a selected energy level and deliver
protons with the desired energy at a selected point in time, such as at
the bottom of the breath. More particularly, the main controller injects
protons into the synchrotron and accelerates the protons in a manner that
combined with extraction delivers the protons to the tumor at a selected
point in the respiration cycle. Intensity of the proton beam is also
selectable and controllable by the main controller at this stage. The
feedback control to the correction coils allows rapid selection of energy
levels of the synchrotron that are tied to the patient's respiration
cycle. This system is in stark contrast to a system where the current is
stabilized and the synchrotron deliver pulses with a period, such as 10
or 20 cycles per second with a fixed period. Optionally, the feedback or
the magnetic field design coupled with the correction coils allows for
the extraction cycle to match the varying respiratory rate of the
patient.

[0191]Traditional extraction systems do not allow this control as magnets
have memories in terms of both magnitude and amplitude of a sine wave.
Hence, in a traditional system, in order to change frequency, slow
changes in current must be used. However, with the use of the feedback
loop using the magnetic field sensors, the frequency and energy level of
the synchrotron are rapidly adjustable. Further aiding this process is
the use of a novel extraction system that allows for acceleration of the
protons during the extraction process, described infra.

[0192]Referring again to FIG. 16, an example of a winding coil 1630 that
covers two turning magnets 1010, 1020 is provided. Optionally, a first
winding coil 1640 covers two magnets and a second winding coil, not
illustrated, covers another two magnets. As described, supra, this system
reduces space between turning section allowing more magnetic field to be
applied per radian of turn. A first correction coil 1610 is illustrated
that is used to correct the magnetic field for the first turning magnet
1010. A second correction coil 1620 is illustrated that is used to
correct the magnetic field for a winding coil 1630 about two turning
magnets. Individual correction coils for each turning magnet are
preferred and individual correction coils yield the most precise and/or
accurate magnetic field in each turning section. Particularly, the
individual correction coil 1610 is used to compensate for imperfections
in the individual magnet of a given turning section. Hence, with a series
of magnetic field sensors, corresponding magnetic fields are individually
adjustable in a series of feedback loops, via a magnetic field monitoring
system, as an independent coil is used for each turning section.
Alternatively, a multiple magnet correction coil is used to correct the
magnetic field for a plurality of turning section magnets.

Proton Beam Extraction

[0193]Referring now to FIG. 19, an exemplary proton extraction process
from the synchrotron 130 is illustrated. For clarity, FIG. 19 removes
elements represented in FIG. 2, such as the turning magnets, which allows
for greater clarity of presentation of the proton beam path as a function
of time. Generally, protons are extracted from the synchrotron 130 by
slowing the protons. As described, supra, the protons were initially
accelerated in a circulating path 264, which is maintained with a
plurality of main bending magnets 250. The circulating path is referred
to herein as an original central beamline 264. The protons repeatedly
cycle around a central point in the synchrotron 280. The proton path
traverses through a radio frequency (RF) cavity system 1910. To initiate
extraction, an RF field is applied across a first blade 1912 and a second
blade 1914, in the RF cavity system 1910. The first blade 1912 and second
blade 1914 are referred to herein as a first pair of blades.

[0194]In the proton extraction process, an RF voltage is applied across
the first pair of blades, where the first blade 1912 of the first pair of
blades is on one side of the circulating proton beam path 264 and the
second blade 1914 of the first pair of blades is on an opposite side of
the circulating proton beam path 264. The applied RF field applies energy
to the circulating charged-particle beam. The applied RF field alters the
orbiting or circulating beam path slightly of the protons from the
original central beamline 264 to an altered circulating beam path 265.
Upon a second pass of the protons through the RF cavity system, the RF
field further moves the protons off of the original proton beamline 264.
For example, if the original beamline is considered as a circular path,
then the altered beamline is slightly elliptical. The applied RF field is
timed to apply outward or inward movement to a given band of protons
circulating in the synchrotron accelerator. Each orbit of the protons is
slightly more off axis compared to the original circulating beam path
264. Successive passes of the protons through the RF cavity system are
forced further and further from the original central beamline 264 by
altering the direction and/or intensity of the RF field with each
successive pass of the proton beam through the RF field.

[0195]The RF voltage is frequency modulated at a frequency about equal to
the period of one proton cycling around the synchrotron for one
revolution or at a frequency than is an integral multiplier of the period
of one proton cycling about the synchrotron. The applied RF frequency
modulated voltage excites a betatron oscillation. For example, the
oscillation is a sine wave motion of the protons. The process of timing
the RF field to a given proton beam within the RF cavity system is
repeated thousands of times with each successive pass of the protons
being moved approximately one micrometer further off of the original
central beamline 264. For clarity, the approximately 1000 changing beam
paths with each successive path of a given band of protons through the RF
field are illustrated as the altered beam path 265.

[0196]With a sufficient sine wave betatron amplitude, the altered
circulating beam path 265 touches or traverses a material 1930, such as a
foil or a sheet of foil. The foil is preferably a lightweight material,
such as beryllium, a lithium hydride, a carbon sheet, or a material
having low nuclear charge components. Herein, a material of low nuclear
charge is a material composed of atoms consisting essentially of atoms
having six or fewer protons. The foil is preferably about 10 to 150
microns thick, is more preferably about 30 to 100 microns thick, and is
still more preferably about 40 to 60 microns thick. In one example, the
foil is beryllium with a thickness of about 50 microns. When the protons
traverse through the foil, energy of the protons is lost and the speed of
the protons is reduced. Typically, a current is also generated, described
infra. Protons moving at a slower speed travel in the synchrotron with a
reduced radius of curvature 266 compared to either the original central
beamline 264 or the altered circulating path 265. The reduced radius of
curvature 266 path is also referred to herein as a path having a smaller
diameter of trajectory or a path having protons with reduced energy. The
reduced radius of curvature 266 is typically about two millimeters less
than a radius of curvature of the last pass of the protons along the
altered proton beam path 265.

[0197]The thickness of the material 1930 is optionally adjusted to created
a change in the radius of curvature, such as about 1/2, 1, 2, 3, or 4 mm
less than the last pass of the protons 265 or original radius of
curvature 264. Protons moving with the smaller radius of curvature travel
between a second pair of blades. In one case, the second pair of blades
is physically distinct and/or is separated from the first pair of blades.
In a second case, one of the first pair of blades is also a member of the
second pair of blades. For example, the second pair of blades is the
second blade 1914 and a third blade 1916 in the RF cavity system 1910. A
high voltage DC signal, such as about 1 to 5 kV, is then applied across
the second pair of blades, which directs the protons out of the
synchrotron through an extraction magnet 292, such as a Lamberson
extraction magnet, into a transport path 268.

[0198]Control of acceleration of the charged particle beam path in the
synchrotron with the accelerator and/or applied fields of the turning
magnets in combination with the above described extraction system allows
for control of the intensity of the extracted proton beam, where
intensity is a proton flux per unit time or the number of protons
extracted as a function of time. For example, when a current is measured
beyond a threshold, the RF field modulation in the RF cavity system is
terminated or reinitiated to establish a subsequent cycle of proton beam
extraction. This process is repeated to yield many cycles of proton beam
extraction from the synchrotron accelerator.

[0199]Because the extraction system does not depend on any change in
magnetic field properties, it allows the synchrotron to continue to
operate in acceleration or deceleration mode during the extraction
process. Stated differently, the extraction process does not interfere
with synchrotron acceleration. In stark contrast, traditional extraction
systems introduce a new magnetic field, such as via a hexapole, during
the extraction process. More particularly, traditional synchrotrons have
a magnet, such as a hexapole magnet, that is off during an acceleration
stage. During the extraction phase, the hexapole magnetic field is
introduced to the circulating path of the synchrotron. The introduction
of the magnetic field necessitates two distinct modes, an acceleration
mode and an extraction mode, which are mutually exclusive in time. The
herein described system allows for acceleration and/or deceleration of
the proton during the extraction step without the use of a newly
introduced magnetic field, such as by a hexapole magnet.

Charged Particle Beam Intensity Control

[0200]Control of applied field, such as a radio-frequency (RF) field,
frequency and magnitude in the RF cavity system 1910 allows for intensity
control of the extracted proton beam, where intensity is extracted proton
flux per unit time or the number of protons extracted as a function of
time.

[0201]Referring still to FIG. 19, when protons in the proton beam hit the
material 1930 electrons are given off resulting in a current. The
resulting current is converted to a voltage and is used as part of a ion
beam intensity monitoring system or as part of an ion beam feedback loop
for controlling beam intensity. The voltage is optionally measured and
sent to the main controller 110 or to a controller subsystem 1940. More
particularly, when protons in the charged particle beam path pass through
the material 1930, some of the protons lose a small fraction of their
energy, such as about one-tenth of a percent, which results in a
secondary electron. That is, protons in the charged particle beam push
some electrons when passing through material 1930 giving the electrons
enough energy to cause secondary emission. The resulting electron flow
results in a current or signal that is proportional to the number of
protons going through the target material 1930. The resulting current is
preferably converted to voltage and amplified. The resulting signal is
referred to as a measured intensity signal.

[0202]The amplified signal or measured intensity signal resulting from the
protons passing through the material 1930 is preferably used in
controlling the intensity of the extracted protons. For example, the
measured intensity signal is compared to a goal signal, which is
predetermined in an irradiation of the tumor plan. The difference between
the measured intensity signal and the planned for goal signal is
calculated. The difference is used as a control to the RF generator.
Hence, the measured flow of current resulting from the protons passing
through the material 1930 is used as a control in the RF generator to
increase or decrease the number of protons undergoing betatron
oscillation and striking the material 1930. Hence, the voltage determined
off of the material 1930 is used as a measure of the orbital path and is
used as a feedback control to control the RF cavity system.
Alternatively, the measured intensity signal is not used in the feedback
control and is just used as a monitor of the intensity of the extracted
protons.

[0203]As described, supra, the photons striking the material 1930 is a
step in the extraction of the protons from the synchrotron 130. Hence,
the measured intensity signal is used to change the number of protons per
unit time being extracted, which is referred to as intensity of the
proton beam. The intensity of the proton beam is thus under algorithm
control. Further, the intensity of the proton beam is controlled
separately from the velocity of the protons in the synchrotron 130.
Hence, intensity of the protons extracted and the energy of the protons
extracted are independently variable.

[0204]For example, protons initially move at an equilibrium trajectory in
the synchrotron 130. An RF field is used to excite the protons into a
betatron oscillation. In one case, the frequency of the protons orbit is
about 10 MHz. In one example, in about one millisecond or after about
10,000 orbits, the first protons hit an outer edge of the target material
130. The specific frequency is dependent upon the period of the orbit.
Upon hitting the material 130, the protons push electrons through the
foil to produce a current. The current is converted to voltage and
amplified to yield a measured intensity signal. The measured intensity
signal is used as a feedback input to control the applied RF magnitude,
RF frequency, or RF field. Preferably, the measured intensity signal is
compared to a target signal and a measure of the difference between the
measured intensity signal and target signal is used to adjust the applied
RF field in the RF cavity system 1910 in the extraction system to control
the intensity of the protons in the extraction step. Stated again, the
signal resulting from the protons striking and/or passing through the
material 130 is used as an input in RF field modulation. An increase in
the magnitude of the RF modulation results in protons hitting the foil or
material 130 sooner. By increasing the RF, more protons are pushed into
the foil, which results in an increased intensity, or more protons per
unit time, of protons extracted from the synchrotron 130.

[0205]In another example, a detector 1830 external to the synchrotron 130
is used to determine the flux of protons extracted from the synchrotron
and a signal from the external detector is used to alter the RF field or
RF modulation in the RF cavity system 1910. Here the external detector
generates an external signal, which is used in a manner similar to the
measured intensity signal, described in the preceding paragraphs.

[0206]In yet another example, when a current from material 130 resulting
from protons passing through or hitting material is measured beyond a
threshold, the RF field modulation in the RF cavity system is terminated
or reinitiated to establish a subsequent cycle of proton beam extraction.
This process is repeated to yield many cycles of proton beam extraction
from the synchrotron accelerator.

[0207]In still yet another embodiment, intensity modulation of the
extracted proton beam is controlled by the main controller 110. The main
controller 110 optionally and/or additionally controls timing of
extraction of the charged particle beam and energy of the extracted
proton beam.

[0208]The benefits of the system include a multi-dimensional scanning
system. Particularly, the system allows independence in: (1) energy of
the protons extracted and (2) intensity of the protons extracted. That
is, energy of the protons extracted is controlled by an energy control
system and an intensity control system controls the intensity of the
extracted protons. The energy control system and intensity control system
are optionally independently controlled. Preferably, the main controller
110 controls the energy control system and the main controller
simultaneously controls the intensity control system to yield an
extracted proton beam with controlled energy and controlled intensity
where the controlled energy and controlled intensity are independently
variable. Thus the irradiation spot hitting the tumor is under
independent control of: [0209]time; [0210]energy; [0211]intensity;
[0212]x-axis position, where the x-axis represents horizontal movement of
the proton beam relative to the patient, and [0213]y-axis position, where
the y-axis represents vertical movement of the proton beam relative to
the patient.

[0214]In addition, the patient is optionally independently translated
and/or rotated relative to a translational axis of the proton beam at the
same time.

[0215]Referring now to FIGS. 20 A and B, a proton beam position
verification system 2000 is described. A nozzle 2010 provides an outlet
for the second reduced pressure vacuum system initiating at the foil 395
of the tandem accelerator 390 and running through the synchrotron 130 to
a nozzle foil 2020 covering the end of the nozzle 2010. The nozzle
expands in x-, y-cross-sectional area along the z-axis of the proton beam
path 268 to allow the proton beam 268 to be scanned along the x- and
y-axes by the vertical control element 142 and horizontal control element
144, respectively. The nozzle foil 2020 is preferably mechanically
supported by the outer edges of an exit port of the nozzle 2010. An
example of a nozzle foil 2020 is a sheet of about 0.1 inch thick aluminum
foil. Generally, the nozzle foil separates atmosphere pressures on the
patient side of the nozzle foil 2020 from the low pressure region, such
as about 10-5 to 10-7 torr region, on the synchrotron 130 side
of the nozzle foil 2020. The low pressure region is maintained to reduce
scattering of the proton beam 264, 268.

[0216]Still referring to FIG. 20, the proton beam verification system 2000
is a system that allows for monitoring of the actual proton beam position
268, 269 in real-time without destruction of the proton beam. The proton
beam verification system 2000 preferably includes a proton beam position
verification layer 2030, which is also referred to herein as a coating,
luminescent, fluorescent, phosphorescent, radiance, or viewing layer. The
verification layer or coating layer 2030 is preferably a coating or thin
layer substantially in contact with an inside surface of the nozzle foil
2020, where the inside surface is on the synchrotron side of the nozzle
foil 2020. Less preferably, the verification layer or coating layer 2030
is substantially in contact with an outer surface of the nozzle foil
2020, where the outer surface is on the patient treatment side of the
nozzle foil 2020. Preferably, the nozzle foil 2020 provides a substrate
surface for coating by the coating layer. Optionally, a binding layer is
located between the coating layer 2030 and the nozzle foil 2020.
Optionally a separate coating layer support element, on which the coating
2030 is mounted, is placed anywhere in the proton beam path 268.

[0217]Referring now to FIG. 20B, the coating 2030 yields a measurable
spectroscopic response, spatially viewable by the detector 2040, as a
result of transmission by the proton beam 268. The coating 2030 is
preferably a phosphor, but is optionally any material that is viewable or
imaged by a detector where the material changes spectroscopically as a
result of the proton beam path 268 hitting or transmitting through the
coating 2030. A detector or camera 2040 views the coating layer 2030 and
determines the current position of the proton beam 269 by the
spectroscopic differences resulting from protons passing through the
coating layer. For example, the camera 2040 views the coating surface
2030 as the proton beam 268 is being scanned by the horizontal 144 and
vertical 142 beam position control elements during treatment of the tumor
2120. The camera 2040 views the current position of the proton beam 269
as measured by spectroscopic response. The coating layer 2030 is
preferably a phosphor or luminescent material that glows or emits photons
for a short period of time, such as less than 5 seconds for a 50%
intensity, as a result of excitation by the proton beam 268. Optionally,
a plurality of cameras or detectors 2040 are used, where each detector
views all or a portion of the coating layer 2030. For example, two
detectors 2040 are used where a first detector views a first half of the
coating layer and the second detector views a second half of the coating
layer. Preferably, at least a portion of the detector 2040 is mounted
into the nozzle 2010 to view the proton beam position after passing
through the first axis and second axis controllers 142, 144. Preferably,
the coating layer 2030 is positioned in the proton beam path 268 in a
position prior to the protons striking the patient 2130.

[0218]Still referring to FIG. 20, the main controller 130, connected to
the camera or detector 2040 output, compares the actual proton beam
position 269 with the planned proton beam position and/or a calibration
reference to determine if the actual proton beam position 269 is within
tolerance. The proton beam verification system 2000 preferably is used in
at least two phases, a calibration phase and a proton beam treatment
phase. The calibration phase is used to correlate, as a function of x-,
y-position of the glowing response the actual x-, y-position of the
proton beam at the patient interface. During the proton beam treatment
phase, the proton beam position is monitored and compared to the
calibration and/or treatment plan to verify accurate proton delivery to
the tumor 2120 and/or as a proton beam shutoff safety indicator.

Patient Positioning

[0219]Referring now to FIG. 21, the patient is preferably positioned on or
within a patient translation and rotation positioning system 2110 of the
patient interface module 150. The patient translation and rotation
positioning system 2110 is used to translate the patient and/or rotate
the patient into a zone where the proton beam can scan the tumor using a
scanning system 140 or proton targeting system, described infra.
Essentially, the patient positioning system 2110 performs large movements
of the patient to place the tumor near the center of a proton beam path
268 and the proton scanning or targeting system 140 performs fine
movements of the momentary beam position 269 in targeting the tumor 2120.
To illustrate, FIG. 21A shows the momentary proton beam position 269 and
a range of scannable positions 2140 using the proton scanning or
targeting system 140, where the scannable positions 2140 are about the
tumor 2120 of the patient 2130. In this example, the scannable positions
are scanned along the x- and y-axes; however, scanning is optionally
simultaneously performed along the z-axis as described infra. This
illustratively shows that the y-axis movement of the patient occurs on a
scale of the body, such as adjustment of about 1, 2, 3, or 4 feet, while
the scannable region of the proton beam 268 covers a portion of the body,
such as a region of about 1, 2, 4, 6, 8, 10, or 12 inches. The patient
positioning system and its rotation and/or translation of the patient
combines with the proton targeting system to yield precise and/or
accurate delivery of the protons to the tumor.

[0220]Referring still to FIG. 21, the patient positioning system 2110
optionally includes a bottom unit 2112 and a top unit 2114, such as discs
or a platform. Referring now to FIG. 21A, the patient positioning unit
2110 is preferably y-axis adjustable 2116 to allow vertical shifting of
the patient relative to the proton therapy beam 268. Preferably, the
vertical motion of the patient positioning unit 2110 is about 10, 20, 30,
or 50 centimeters per minute. Referring now to FIG. 21B, the patient
positioning unit 2110 is also preferably rotatable 2117 about a rotation
axis, such as about the y-axis running through the center of the bottom
unit 2112 or about a y-axis running through the tumor 2120, to allow
rotational control and positioning of the patient relative to the proton
beam path 268. Preferably the rotational motion of the patient
positioning unit 2110 is about 360 degrees per minute. Optionally, the
patient positioning unit rotates about 45, 90, or 180 degrees.
Optionally, the patient positioning unit 2110 rotates at a rate of about
45, 90, 180, 360, 720, or 1080 degrees per minute. The rotation of the
positioning unit 2117 is illustrated about the rotation axis at two
distinct times, t1 and t2. Protons are optionally delivered to
the tumor 2120 at n times where each of the n times represent a different
relative direction of the incident proton beam 269 hitting the patient
2130 due to rotation of the patient 2117 about the rotation axis.

[0221]Any of the semi-vertical, sitting, or laying patient positioning
embodiments described, infra, are optionally vertically translatable
along the y-axis or rotatable about the rotation or y-axis.

[0222]Preferably, the top and bottom units 2112, 2114 move together, such
that they rotate at the same rates and translate in position at the same
rates. Optionally, the top and bottom units 2112, 2114 are independently
adjustable along the y-axis to allow a difference in distance between the
top and bottom units 2112, 2114. Motors, power supplies, and mechanical
assemblies for moving the top and bottom units 2112, 2114 are preferably
located out of the proton beam path 269, such as below the bottom unit
2112 and/or above the top unit 2114. This is preferable as the patient
positioning unit 2110 is preferably rotatable about 360 degrees and the
motors, power supplies, and mechanical assemblies interfere with the
protons if positioned in the proton beam path 269

Proton Delivery Efficiency

[0223]Referring now to FIG. 22, a common distribution of relative doses
for both X-rays and proton irradiation is presented. As shown, X-rays
deposit their highest dose near the surface of the targeted tissue and
then deposited doses exponentially decrease as a function of tissue
depth. The deposition of X-ray energy near the surface is non-ideal for
tumors located deep within the body, which is usually the case, as
excessive damage is done to the soft tissue layers surrounding the tumor
2120. The advantage of protons is that they deposit most of their energy
near the end of the flight trajectory as the energy loss per unit path of
the absorber transversed by a proton increases with decreasing particle
velocity, giving rise to a sharp maximum in ionization near the end of
the range, referred to herein as the Bragg peak. Furthermore, since the
flight trajectory of the protons is variable by increasing or decreasing
the initial kinetic energy or initial velocity of the proton, then the
peak corresponding to maximum energy is movable within the tissue. Thus
z-axis control of the proton depth of penetration is allowed by the
acceleration/extraction process, described supra. As a result of proton
dose-distribution characteristics, using the algorithm described, infra,
a radiation oncologist can optimize dosage to the tumor 2120 while
minimizing dosage to surrounding normal tissues.

[0224]Herein, the term ingress refers to a place charged particles enter
into the patient 2130 or a place of charged particles entering the tumor
2120. The ingress region of the Bragg energy profile refers to the
relatively flat dose delivery portion at shallow depths of the Bragg
energy profile. Similarly, herein the terms proximal or the clause
proximal region refer to the shallow depth region of the tissue that
receives the relatively flat radiation dose delivery portion of the
delivered Bragg profile energy. Herein, the term distal refers to the
back portion of the tumor located furthest away from the point of origin
where the charged particles enter the tumor. In terms of the Bragg energy
profile, the Bragg peak is at the distal point of the profile. Herein,
the term ventral refers to the front of the patient and the term dorsal
refers to the back of the patient. As an example of use, when delivering
protons to a tumor in the body, the protons ingress through the healthy
tissue and if delivered to the far side of the tumor, the Bragg peak
occurs at the distal side of the tumor. For a case where the proton
energy is not sufficient to reach the far side of the tumor, the distal
point of the Bragg energy profile is the region of furthest penetration
into the tumor.

[0225]The Bragg peak energy profile shows that protons deliver their
energy across the entire length of the body penetrated by the proton up
to a maximum penetration depth. As a result, energy is being delivered,
in the proximal portion of the Bragg peak energy profile, to healthy
tissue, bone, and other body constituents before the proton beam hits the
tumor. It follows that the shorter the pathlength in the body prior to
the tumor, the higher the efficiency of proton delivery efficiency, where
proton delivery efficiency is a measure of how much energy is delivered
to the tumor relative to healthy portions of the patient. Examples of
proton delivery efficiency include: (1) a ratio of proton energy
delivered to the tumor over proton energy delivered to non-tumor tissue;
(2) pathlength of protons in the tumor versus pathlength in the non-tumor
tissue; and/or (3) damage to a tumor compared to damage to healthy body
parts. Any of these measures are optionally weighted by damage to
sensitive tissue, such as a nervous system element, heart, brain, or
other organ. To illustrate, for a patient in a laying position where the
patient is rotated about the y-axis during treatment, a tumor near the
heart would at times be treated with protons running through the
head-to-heart path, leg-to-heart path, or hip-to-heart path, which are
all inefficient compared to a patient in a sitting or semi-vertical
position where the protons are all delivered through a shorter
chest-to-heart; side-of-body-to-heart, or back-to-heart path.
Particularly, compared to a laying position, using a sitting or
semi-vertical position of the patient, a shorter pathlength through the
body to a tumor is provided to a tumor located in the torso or head,
which results in a higher or better proton delivery efficiency.

[0226]Herein proton delivery efficiency is separately described from time
efficiency or synchrotron use efficiency, which is a fraction of time
that the charged particle beam apparatus is in a tumor treating operation
mode.

Depth Targeting

[0227]Referring now to FIGS. 23 A-E, x-axis scanning of the proton beam is
illustrated while z-axis energy of the proton beam undergoes controlled
variation 2300 to allow irradiation of slices of the tumor 2120. For
clarity of presentation, the simultaneous y-axis scanning that is
performed is not illustrated. In FIG. 23A, irradiation is commencing with
the momentary proton beam position 269 at the start of a first slice.
Referring now to FIG. 23B, the momentary proton beam position is at the
end of the first slice. Importantly, during a given slice of irradiation,
the proton beam energy is preferably continuously controlled and changed
according to the tissue mass and density in front of the tumor 2120. The
variation of the proton beam energy to account for tissue density thus
allows the beam stopping point, or Bragg peak, to remain inside the
tissue slice. The variation of the proton beam energy during scanning or
during x-, y-axes scanning is possible due to the acceleration/extraction
techniques, described supra, which allow for acceleration of the proton
beam during extraction. FIGS. 23C, 23D, and 23E show the momentary proton
beam position in the middle of the second slice, two-thirds of the way
through a third slice, and after finalizing irradiation from a given
direction, respectively. Using this approach, controlled, accurate, and
precise delivery of proton irradiation energy to the tumor 2120, to a
designated tumor subsection, or to a tumor layer is achieved. Efficiency
of deposition of proton energy to tumor, as defined as the ratio of the
proton irradiation energy delivered to the tumor relative to the proton
irradiation energy delivered to the healthy tissue is further described
infra.

Multi-Field Irradiation

[0228]It is desirable to maximize efficiency of deposition of protons to
the tumor 2120, as defined by maximizing the ratio of the proton
irradiation energy delivered to the tumor 2120 relative to the proton
irradiation energy delivered to the healthy tissue. Irradiation from one,
two, or three directions into the body, such as by rotating the body
about 90 degrees between irradiation sub-sessions results in proton
irradiation from the proximal portion of the Bragg peak concentrating
into one, two, or three healthy tissue volumes, respectively. It is
desirable to further distribute the proximal portion of the Bragg peak
energy evenly through the healthy volume tissue surrounding the tumor
2120.

[0229]Multi-field irradiation is proton beam irradiation from a plurality
of entry points into the body. For example, the patient 2130 is rotated
and the radiation source point is held constant. For example, the patient
2130 is rotated through 360 degrees and proton therapy is applied from a
multitude of angles resulting in the ingress or proximal radiation being
circumferentially spread about the tumor yielding enhanced proton
irradiation efficiency. In one case, the body is rotated into greater
than 3, 5, 10, 15, 20, 25, 30, or 35 positions and proton irradiation
occurs with each rotation position. Rotation of the patient is preferably
performed using the patient positioning system 2110 and/or the bottom
unit 2112 or disc, described supra. Rotation of the patient 2130 while
keeping the delivery proton beam 268 in a relatively fixed orientation
allows irradiation of the tumor 2120 from multiple directions without use
of a new collimator for each direction. Further, as no new setup is
required for each rotation position of the patient 2130, the system
allows the tumor 2120 to be treated from multiple directions without
reseating or positioning the patient, thereby minimizing tumor 2120
regeneration time, increasing the synchrotrons efficiency, and increasing
patient throughput.

[0230]The patient is optionally centered on the bottom unit 2112 or the
tumor 2120 is optionally centered on the bottom unit 2112. If the patient
is centered on the bottom unit 2112, then the first axis control element
142 and second axis control element 144 are programmed to compensate for
the off central axis of rotation position variation of the tumor 2120.

[0231]Referring now to FIGS. 24 A-E, an example of multi-field irradiation
2400 is presented. In this example, five patient rotation positions are
illustrated; however, the five rotation positions are discrete rotation
positions of about thirty-six rotation positions, where the body is
rotated about ten degrees with each position. Referring now to FIG. 24A,
a range of irradiation beam positions 269 is illustrated from a first
body rotation position, illustrated as the patient 2130 facing the proton
irradiation beam where the tumor receives the bulk of the Bragg profile
energy while a first healthy volume 2411 is irradiated by the less
intense ingress portion of the Bragg profile energy. Referring now to
FIG. 24B, the patient 2130 is rotated about forty degrees and the
irradiation is repeated. In the second position, the tumor 2120 again
receives the bulk of the irradiation energy and a second healthy tissue
volume 2412 receives the smaller ingress portion of the Bragg profile
energy. Referring now to FIGS. 24 C-E, the patient 2130 is rotated a
total of about 90, 130, and 180 degrees, respectively. For each of the
third, fourth, and fifth rotation positions, the tumor 2120 receives the
bulk of the irradiation energy and the third, fourth, and fifth healthy
tissue volumes 2413, 2414, 1415 receive the smaller ingress portion of
the Bragg peak energy, respectively. Thus, the rotation of the patient
during proton therapy results in the proximal or ingress energy of the
delivered proton energy to be distributed about the tumor 2120, such as
to regions one to five 2411-2415, while along a given axis, at least
about 75, 80, 85, 90, or 95 percent of the energy is delivered to the
tumor 2120.

[0232]For a given rotation position, all or part of the tumor is
irradiated. For example, in one embodiment only a distal section or
distal slice of the tumor 2120 is irradiated with each rotation position,
where the distal section is a section furthest from the entry point of
the proton beam into the patient 2130. For example, the distal section is
the dorsal side of the tumor when the patient 2130 is facing the proton
beam and the distal section is the ventral side of the tumor when the
patient 2130 is facing away from the proton beam.

[0233]Referring now to FIG. 25, a second example of multi-field
irradiation 2500 is presented where the proton source is stationary and
the patient 2130 is rotated. For ease of presentation, the stationary but
scanning proton beam path 269 is illustrated as entering the patient 2130
from varying sides at times t1, t2, t3, . . . , tn,
tn+1 as the patient is rotated. At a first time, t1, the
ingress side or proximal region of the Bragg peak profile hits a first
area, A1. Again, the proximal end of the Bragg peak profile refers
to the relatively shallow depths of tissue where Bragg energy profile
energy delivery is relatively flat. The patient is rotated and the proton
beam path is illustrated at a second time, t2, where the ingress
energy of the Bragg energy profile hits a second area, A2. Thus, the
low radiation dosage of the ingress region of the Bragg profile energy is
delivered to the second area. At a third time, the ingress end of the
Bragg energy profile hits a third area, A3. This rotation and
irradiation process is repeated n times, where n is a positive number
greater than five and preferably greater than about 10, 20, 30, 100, or
300. As illustrated, at an nth time, tn, if the patient 2130 is
rotated further, the scanning proton beam 269 would hit a sensitive body
constituent 2150, such as the spinal cord or eyes. Irradiation is
preferably suspended until the sensitive body constituent is rotated out
of the scanning proton beam 269 path. Irradiation is resumed at a time,
tn+1, after the sensitive body constituent 2150 is rotated out of
the proton beam path. In this manner: [0234]the distal Bragg peak
energy is always within the tumor; [0235]the radiation dose delivery of
the distal region of the Bragg energy profile is spread over the tumor;
[0236]the ingress or proximal region of the Bragg energy profile is
distributed in healthy tissue about the tumor 2120; and [0237]sensitive
body constituents 2150 receive minimal or no proton beam irradiation.

Proton Delivery Efficiency

[0238]Herein, charged particle or proton delivery efficiency is radiation
dose delivered to the tumor compared to radiation dose delivered to the
healthy regions of the patient.

[0239]A proton delivery enhancement method is described where proton
delivery efficiency is enhanced, optimized, or maximized. In general,
multi-field irradiation is used to deliver protons to the tumor from a
multitude of rotational directions. From each direction, the energy of
the protons is adjusted to target the distal portion of the tumor, where
the distal portion of the tumor is the volume of the tumor furthest from
the entry point of the proton beam into the body.

[0240]For clarity, the process is described using an example where the
outer edges of the tumor are initially irradiated using distally applied
radiation through a multitude of rotational positions, such as through
360 degrees. This results in a symbolic or calculated remaining smaller
tumor for irradiation. The process is then repeated as many times as
necessary on the smaller tumor. However, the presentation is for clarity.
In actuality, irradiation from a given rotational angle is performed once
with z-axis proton beam energy and intensity being adjusted for the
calculated smaller inner tumors during x- and y-axis scanning.

[0241]Referring now to FIG. 26, the proton delivery enhancement method is
further described. Referring now to FIG. 26A, at a first point in time
protons are delivered to the tumor 2120 of the patient 2130 from a first
direction. From the first rotational direction, the proton beam is
scanned 269 across the tumor. As the proton beam is scanned across the
tumor the energy of the proton beam is adjusted to allow the Bragg peak
energy to target the distal portion of the tumor. Again, distal refers to
the back portion of the tumor located furthest away from where the
charged particles enter the tumor. As illustrated, the proton beam is
scanned along an x-axis across the patient. This process allows the Bragg
peak energy to fall within the tumor, for the middle area of the Bragg
peak profile to fall in the middle and proximal portion of the tumor, and
for the small intensity ingress portion of the Bragg peak to hit healthy
tissue. In this manner, the maximum radiation dose is delivered to the
tumor or the proton dose efficiency is maximized for the first rotational
direction.

[0242]After irradiation from the first rotational position, the patient is
rotated to a new rotational position. Referring now to FIG. 26B, the
scanning of the proton beam is repeated. Again, the distal portion of the
tumor is targeted with adjustment of the proton beam energy to target the
Bragg peak energy to the distal portion of the tumor. Naturally, the
distal portion of the tumor for the second rotational position is
different from the distal portion of the tumor for the first rotational
position. Referring now to FIG. 26C, the distal irradiation is
illustrated from a third rotational direction. Referring now to FIG. 26C,
the process of rotating the patient and then irradiating the new distal
portion of the tumor is further illustrated at an nth rotational
position. Preferably, the process of rotating the patient and scanning
along the x- and y-axes with the Z-axes energy targeting the new distal
portion of the tumor is repeated, such as with more than 5, 10, 20, or 30
rotational positions or with about 36 rotational positions.

[0243]For clarity, FIGS. 26 A-C and FIG. 26 E show the proton beam as
having moved, but in actuality, the proton beam is stationary and the
patient is rotated, such as via use of rotating the bottom unit 2112 of
the patient positioning system 2110. Also, FIGS. 26 A-C show the proton
beam being scanned across the tumor along the x-axis. Though not
illustrated for clarity, the proton beam is additionally scanned up and
down the tumor along the y-axis of the patient. Combined, the distal
portion or volume of the tumor is irradiated along the x- and y-axes with
adjustment of the z-axis energy level of the proton beam. In one case,
the tumor is scanned along the x-axis and the scanning is repeated along
the x-axis for multiple y-axis positions. In another case, the tumor is
scanned along the y-axis and the scanning is repeated along the y-axis
for multiple x-axis positions. In yet another case, the tumor is scanned
by simultaneously adjusting the x- and y-axes so that the distal portion
of the tumor is targeted. In all of these cases, the z-axis or energy of
the proton beam is adjusted along the contour of the distal portion of
the tumor to target the Bragg peak energy to the distal portion of the
tumor.

[0244]Referring now to FIG. 26D, after targeting the distal portion of the
tumor from multiple directions, such as through 360 degrees, the outer
perimeter of the tumor has been strongly irradiated with peak Bragg
profile energy, the middle of the Bragg peak energy profile energy has
been delivered along an inner edge of the heavily irradiated tumor
perimeter, and smaller dosages from the ingress portion of the Bragg
energy profile are distributed throughout the tumor and into some healthy
tissue. The delivered dosages or accumulated radiation flux levels are
illustrated in a cross-sectional area of the tumor 2120 using an iso-line
plot. After a first full rotation of the patient, symbolically, the
darkest regions of the tumor are nearly fully irradiated and the regions
of the tissue having received less radiation are illustrated with a gray
scale with the whitest portions having the lowest radiation dose.

[0245]Referring now to FIG. 26E, after completing the distal targeting
multi-field irradiation, a smaller inner tumor is defined, where the
inner tumor is already partially irradiated. The smaller inner tumor is
indicated by the dashed line 2630. The above process of irradiating the
tumor is repeated for the newly defined smaller tumor. The proton dosages
to the outer or distal portions of the smaller tumor are adjusted to
account for the dosages delivered from other rotational positions. After
the second tumor is irradiated, a yet smaller third tumor is defined. The
process is repeated until the entire tumor is irradiated at the
prescribed or defined dosage.

[0246]As described at the onset of this example, the patient is preferably
only rotated to each rotational position once. In the above described
example, after irradiation of the outer perimeter of the tumor, the
patient is rotationally positioned, such as through 360 degrees, and the
distal portion of the newest smaller tumor is targeted as described,
supra. However, the irradiation dosage to be delivered to the second
smaller tumor and each subsequently smaller tumor is known a-priori.
Hence, when at a given angle of rotation, the smaller tumor or multiple
progressively smaller tumors, are optionally targeted so that the patient
is only rotated to the multiple rotational irradiation positions once.

[0247]The goal is to deliver a treatment dosage to each position of the
tumor, to preferably not exceed the treatment dosage to any position of
the tumor, to minimize ingress radiation dosage to healthy tissue, to
circumferentially distribute ingress radiation hitting the healthy
tissue, and to further minimize ingress radiation dosage to sensitive
areas. Since the Bragg energy profile is known, it is possible to
calculated the optimal intensity and energy of the proton beam for each
rotational position and for each x- and y-axis scanning position. These
calculation result in slightly less than threshold radiation dosage to be
delivered to the distal portion of the tumor for each rotational position
as the ingress dose energy from other positions bring the total dose
energy for the targeted position up to the threshold delivery dose.

[0248]Referring again to FIG. 26A and FIG. 26C, the intensity of the
proton beam is preferably adjusted to account for the cross-sectional
distance or density of the healthy tissue. An example is used for
clarity. Referring now to FIG. 26A, when irradiating from the first
position where the healthy tissue has a small area 2610, the intensity of
the proton beam is preferably increased as relatively less energy is
delivered by the ingress portion of the Bragg profile to the healthy
tissue. Referring now to FIG. 26C, in contrast when irradiating from the
nth rotational position where the healthy tissue has a large
cross-sectional area, the intensity of the proton beam is preferably
decreased as a greater fraction the proton dose is delivered to the
healthy tissue from this orientation.

[0249]In one example, for each rotational position and/or for each z-axis
distance into the tumor, the efficiency of proton dose delivery to the
tumor is calculated. The intensity of the proton beam is made
proportional to the calculated efficiency. Essentially, when the scanning
direction has really good efficiency, the intensity is increased and
vise-versa. For example, if the tumor is elongated, generally the
efficiency of irradiating the distal portion by going through the length
of the tumor is higher than irradiating a distal region of the tumor by
going across the tumor with the Bragg energy distribution. Generally, in
the optimization algorithm: [0250]distal portions of the tumor are
targeted for each rotational position; [0251]the intensity of the proton
beam is largest with the largest cross-sectional area of the tumor;
[0252]intensity is larger when the intervening healthy tissue volume is
smallest; and [0253]intensity is minimized or cut to zero when the
intervening healthy tissue volume includes sensitive tissue, such as the
spinal cord or eyes.

[0254]Using an algorithm so defined, the efficiency of radiation dose
delivery to the tumor is maximized. More particularly, the ratio of
radiation dose delivered to the tumor versus the radiation dose delivered
to surrounding healthy tissue approaches a maximum. Further, integrated
radiation dose delivery to each x, y, and z-axis volume of the tumor as a
result of irradiation from multiple rotation directions is at or near the
preferred dose level. Still further, ingress radiation dose delivery to
healthy tissue is circumferentially distributed about the tumor via use
of multi-field irradiation where radiation is delivered from a plurality
of directions into the body, such as more than 5, 10, 20, or 30
directions.

Multi-Field Irradiation

[0255]In one multi-field irradiation example, the particle therapy system
with a synchrotron ring diameter of less than six meters includes ability
to: [0256]rotate the patient through about 360 degrees; [0257]extract
radiation in about 0.1 to 10 seconds; [0258]scan vertically about 100
millimeters; [0259]scan horizontally about 700 millimeters; [0260]vary
beam energy from about 30 to 330 MeV/second during irradiation;
[0261]vary the proton beam intensity independently of varying the proton
beam energy; [0262]focus the proton beam with a cross-sectional distance
from about 2 to 20 millimeters at the tumor; and/or [0263]complete
multi-field irradiation of a tumor in less than about 1, 2, 4, or 6
minutes as measured from the time of initiating proton delivery to the
patient 2130.

[0264]Two multi-field irradiation methods are described. In the first
method, the main controller 110 rotationally positions the patient 2130
and subsequently irradiates the tumor 2120. The process is repeated until
a multi-field irradiation plan is complete. In the second method, the
main controller 110 simultaneously rotates and irradiates the tumor 2120
within the patient 2130 until the multi-field irradiation plan is
complete. More particularly, the proton beam irradiation occurs while the
patient 2130 is being rotated.

[0265]The 3-dimensional scanning system of the proton spot focal point,
described herein, is preferably combined with a rotation/raster method.
The method includes layer wise tumor irradiation from many directions.
During a given irradiation slice, the proton beam energy is continuously
changed according to the tissue's density in front of the tumor to result
in the beam stopping point, defined by the Bragg peak, always being
inside the tumor and inside the irradiated slice. The novel method allows
for irradiation from many directions, referred to herein as multi-field
irradiation, to achieve the maximal effective dose at the tumor level
while simultaneously significantly reducing possible side-effects on the
surrounding healthy tissues in comparison to existing methods.
Essentially, the multi-field irradiation system distributes
dose-distribution at tissue depths not yet reaching the tumor.

Proton Beam Position Control

[0266]Referring now to FIGS. 27 A and B, a beam delivery and tissue volume
scanning system is illustrated. Presently, the worldwide radiotherapy
community uses a method of dose field forming using a pencil beam
scanning system. In stark contrast, FIG. 27 illustrates a spot scanning
system or tissue volume scanning system. In the tissue volume scanning
system, the proton beam is controlled, in terms of transportation and
distribution, using an inexpensive and precise scanning system. The
scanning system is an active system, where the beam is focused into a
spot focal point of about one-half, one, two, or three millimeters in
diameter. The focal point is translated along two axes while
simultaneously altering the applied energy of the proton beam, which
effectively changes the third dimension of the focal point. The system is
applicable in combination with the above described rotation of the body,
which preferably occurs in-between individual moments or cycles of proton
delivery to the tumor. Optionally, the rotation of the body by the above
described system occurs continuously and simultaneously with proton
delivery to the tumor.

[0267]For example, in the illustrated system in FIG. 27A, the spot is
translated horizontally, is moved down a vertical y-axis, and is then
back along the horizontal axis. In this example, current is used to
control a vertical scanning system having at least one magnet. The
applied current alters the magnetic field of the vertical scanning system
to control the vertical deflection of the proton beam. Similarly, a
horizontal scanning magnet system controls the horizontal deflection of
the proton beam. The degree of transport along each axes is controlled to
conform to the tumor cross-section at the given depth. The depth is
controlled by changing the energy of the proton beam. For example, the
proton beam energy is decreased, so as to define a new penetration depth,
and the scanning process is repeated along the horizontal and vertical
axes covering a new cross-sectional area of the tumor. Combined, the
three axes of control allow scanning or movement of the proton beam focal
point over the entire volume of the cancerous tumor. The time at each
spot and the direction into the body for each spot is controlled to yield
the desired radiation does at each sub-volume of the cancerous volume
while distributing energy hitting outside of the tumor.

[0268]The focused beam spot volume dimension is preferably tightly
controlled to a diameter of about 0.5, 1, or 2 millimeters, but is
alternatively several centimeters in diameter. Preferred design controls
allow scanning in two directions with: (1) a vertical amplitude of about
100 mm amplitude and frequency up to about 200 Hz; and (2) a horizontal
amplitude of about 700 mm amplitude and frequency up to about 1 Hz.

[0269]In FIG. 27A, the proton beam is illustrated along a z-axis
controlled by the beam energy, the horizontal movement is along an
x-axis, and the vertical direction is along a y-axis. The distance the
protons move along the z-axis into the tissue, in this example, is
controlled by the kinetic energy of the proton. This coordinate system is
arbitrary and exemplary. The actual control of the proton beam is
controlled in 3-dimensional space using two scanning magnet systems and
by controlling the kinetic energy of the proton beam. The use of the
extraction system, described supra, allows for different scanning
patterns. Particularly, the system allows simultaneous adjustment of the
x-, y-, and z-axes in the irradiation of the solid tumor. Stated again,
instead of scanning along an x,y-plane and then adjusting energy of the
protons, such as with a range modulation wheel, the system allows for
moving along the z-axes while simultaneously adjusting the x- and or
y-axes. Hence, rather than irradiating slices of the tumor, the tumor is
optionally irradiated in three simultaneous dimensions. For example, the
tumor is irradiated around an outer edge of the tumor in three
dimensions. Then the tumor is irradiated around an outer edge of an
internal section of the tumor. This process is repeated until the entire
tumor is irradiated. The outer edge irradiation is preferably coupled
with simultaneous rotation of the subject, such as about a vertical
y-axis. This system allows for maximum efficiency of deposition of
protons to the tumor, as defined as the ratio of the proton irradiation
energy delivered to the tumor relative to the proton irradiation energy
delivered to the healthy tissue.

[0270]Combined, the system allows for multi-axes control of the charged
particle beam system in a small space with a small power supply. For
example, the system uses multiple magnets where each magnet has at least
one edge focusing effect in each turning section of the synchrotron
and/or multiple magnets having concentrating magnetic field geometry, as
described supra. The multiple edge focusing effects in the circulating
beam path of the synchrotron combined with the concentration geometry of
the magnets and described extraction system yields a synchrotron having:
[0271]a small circumference system, such as less than about 50 meters;
[0272]a vertical proton beam size gap of about 2 cm; [0273]corresponding
reduced power supply requirements associated with the reduced gap size;
[0274]an extraction system not requiring a newly introduced magnetic
field; [0275]acceleration or deceleration of the protons during
extraction; and [0276]control of z-axis energy during extraction.

[0277]The result is a 3-dimensional scanning system, x-, y-, and z-axes
control, where the z-axes control resides in the synchrotron and where
the z-axes energy is variably controlled during the extraction process
inside the synchrotron.

[0278]Referring now to FIG. 27B, an example of a proton scanning or
targeting system 140 used to direct the protons to the tumor with
4-dimensional scanning control is provided, where the 4-dimensional
scanning control is along the x-, y-, and z-axes along with intensity
control, as described supra. A fifth controllable axis is time. A sixth
controllable axis is patient rotation. Typically, charged particles
traveling along the transport path 268 are directed through a first axis
control element 142, such as a vertical control, and a second axis
control element 144, such as a horizontal control and into a tumor 2120.
As described, supra, the extraction system also allows for simultaneous
variation in the z-axis. Further, as described, supra, the intensity or
dose of the extracted beam is optionally simultaneously and independently
controlled and varied. Thus instead of irradiating a slice of the tumor,
as in FIG. 27A, all four dimensions defining the targeting spot of the
proton delivery in the tumor are simultaneously variable. The
simultaneous variation of the proton delivery spot is illustrated in FIG.
27B by the spot delivery path 269. In the illustrated case, the protons
are initially directed around an outer edge of the tumor and are then
directed around an inner radius of the tumor. Combined with rotation of
the subject about a vertical axis, a multi-field irradiation process is
used where a not yet irradiated portion of the tumor is preferably
irradiated at the further distance of the tumor from the proton entry
point into the body. This yields the greatest percentage of the proton
delivery, as defined by the Bragg peak, into the tumor and minimizes
damage to peripheral healthy tissue.

Imaging/X-Ray System

[0279]Herein, an X-ray system is used to illustrate an imaging system.

Timing

[0280]An X-ray is preferably collected either (1) just before or (2)
concurrently with treating a subject with proton therapy for a couple of
reasons. First, movement of the body, described supra, changes the local
position of the tumor in the body relative to other body constituents. If
the patient or subject 2130 has an X-ray taken and is then bodily moved
to a proton treatment room, accurate alignment of the proton beam to the
tumor is problematic. Alignment of the proton beam to the tumor 2120
using one or more X-rays is best performed at the time of proton delivery
or in the seconds or minutes immediately prior to proton delivery and
after the patient is placed into a therapeutic body position, which is
typically a fixed position or partially immobilized position. Second, the
X-ray taken after positioning the patient is used for verification of
proton beam alignment to a targeted position, such as a tumor and/or
internal organ position.

Positioning

[0281]An X-ray is preferably taken just before treating the subject to aid
in patient positioning. For positioning purposes, an X-ray of a large
body area is not needed. In one embodiment, an X-ray of only a local area
is collected. When collecting an X-ray, the X-ray has an X-ray path. The
proton beam has a proton beam path. Overlaying the X-ray path with the
proton beam path is one method of aligning the proton beam to the tumor.
However, this method involves putting the X-ray equipment into the proton
beam path, taking the X-ray, and then moving the X-ray equipment out of
the beam path. This process takes time. The elapsed time while the X-ray
equipment moves has a couple of detrimental effects. First, during the
time required to move the X-ray equipment, the body moves. The resulting
movement decreases precision and/or accuracy of subsequent proton beam
alignment to the tumor. Second, the time required to move the X-ray
equipment is time that the proton beam therapy system is not in use,
which decreases the total efficiency of the proton beam therapy system.

X-Ray Source Lifetime

[0282]Preferably, components in the particle beam therapy system require
minimal or no maintenance over the lifetime of the particle beam therapy
system. For example, it is desirable to equip the proton beam therapy
system with an X-ray system having a long lifetime source, such as a
lifetime of about 20 years.

[0283]In one system, described infra, electrons are used to create X-rays.
The electrons are generated at a cathode where the lifetime of the
cathode is temperature dependent. Analogous to a light bulb, where the
filament is kept in equilibrium, the cathode temperature is held in
equilibrium at temperatures at about 200, 500, or 1000 degrees Celsius.
Reduction of the cathode temperature results in increased lifetime of the
cathode. Hence, the cathode used in generating the electrons is
preferably held at as low of a temperature as possible. However, if the
temperature of the cathode is reduced, then electron emissions also
decrease. To overcome the need for more electrons at lower temperatures,
a large cathode is used and the generated electrons are concentrated. The
process is analogous to compressing electrons in an electron gun;
however, here the compression techniques are adapted to apply to
enhancing an X-ray tube lifetime.

[0284]Referring now to FIG. 28, an example of an X-ray generation device
2800 having an enhanced lifetime is provided. Electrons 2820 are
generated at a cathode 2810, focused with a control electrode 2812, and
accelerated with a series of accelerating electrodes 2840. The
accelerated electrons 2850 impact an X-ray generation source 2848
resulting in generated X-rays that are then directed along an X-ray path
2970 to the subject 2130. The concentrating of the electrons from a first
diameter 2815 to a second diameter 2816 allows the cathode to operate at
a reduced temperature and still yield the necessary amplified level of
electrons at the X-ray generation source 2848. In one example, the X-ray
generation source 2848 is the anode coupled with the cathode 2810 and/or
the X-ray generation source is substantially composed of tungsten.

[0285]Still referring to FIG. 28, a more detailed description of an
exemplary X-ray generation device 2800 is described. An anode
2814/cathode 2810 pair is used to generated electrons. The electrons 2820
are generated at the cathode 2810 having a first diameter 2815, which is
denoted d1. The control electrodes 2812 attract the generated
electrons 2820. For example, if the cathode is held at about -150 kV and
the control electrode is held at about -149 kV, then the generated
electrons 2820 are attracted toward the control electrodes 2812 and
focused. A series of accelerating electrodes 2840 are then used to
accelerate the electrons into a substantially parallel path 2850 with a
smaller diameter 2816, which is denoted d2. For example, with the
cathode held at -150 kV, a first, second, third, and fourth accelerating
electrodes 2842, 2844, 2846, 2848 are held at about -120, -90, -60, and
-30 kV, respectively. If a thinner body part is to be analyzed, then the
cathode 2810 is held at a smaller level, such as about -90 kV and the
control electrode, first, second, third, and fourth electrode are each
adjusted to lower levels. Generally, the voltage difference from the
cathode to fourth electrode is less for a smaller negative voltage at the
cathode and vise-versa. The accelerated electrons 2850 are optionally
passed through a magnetic lens 2860 for adjustment of beam size, such as
a cylindrical magnetic lens. The electrons are also optionally focused
using quadrupole magnets 2870, which focus in one direction and defocus
in another direction. The accelerated electrons 2850, which are now
adjusted in beam size and focused strike the X-ray generation source
2848, such as tungsten, resulting in generated X-rays that pass through
an optional blocker 2962 and proceed along an X-ray path 2970 to the
subject. The X-ray generation source 2848 is optionally cooled with a
cooling element 2849, such as water touching or thermally connected to a
backside of the X-ray generation source 2848. The concentrating of the
electrons from a first diameter 2815 to a second diameter 2816 allows the
cathode to operate at a reduced temperature and still yield the necessary
amplified level of electrons at the X-ray generation source 2848.

[0286]More generally, the X-ray generation device 2800 produces electrons
having initial vectors. One or more of the control electrode 2812,
accelerating electrodes 2840, magnetic lens 2860, and quadrupole magnets
2870 combine to alter the initial electron vectors into parallel vectors
with a decreased cross-sectional area having a substantially parallel
path, referred to as the accelerated electrons 2850. The process allows
the X-ray generation device 2800 to operate at a lower temperature.
Particularly, instead of using a cathode that is the size of the electron
beam needed, a larger electrode is used and the resulting electrons 2820
are focused and/or concentrated into the required electron beam needed.
As lifetime is roughly an inverse of current density, the concentration
of the current density results in a larger lifetime of the X-ray
generation device. A specific example is provided for clarity. If the
cathode has a fifteen mm radius or d1 is about 30 mm, then the area
(π r2) is about 225 mm2 times pi. If the concentration of
the electrons achieves a radius of five mm or d2 is about 10 mm,
then the area (πr2) is about 25 mm2 times pi. The ratio of
the two areas is about nine (225π/25π). Thus, there is about nine
times less density of current at the larger cathode compared to the
traditional cathode having an area of the desired electron beam. Hence,
the lifetime of the larger cathode approximates nine times the lifetime
of the traditional cathode, though the actual current through the larger
cathode and traditional cathode is about the same. Preferably, the area
of the cathode 2810 is about 2, 4, 6, 8, 10, 15, 20, or 25 times that of
the cross-sectional area of the substantially parallel electron beam
2850.

[0287]In another embodiment of the invention, the quadrupole magnets 2870
result in an oblong cross-sectional shape of the electron beam 2850. A
projection of the oblong cross-sectional shape of the electron beam 2850
onto the X-ray generation source 2848 results in an X-ray beam 2970 that
has a small spot in cross-sectional view, which is preferably
substantially circular in cross-sectional shape, that is then passed
through the patient 2830. The small spot is used to yield an X-ray having
enhanced resolution at the patient.

[0288]Referring now to FIG. 29, in one embodiment, an X-ray is generated
close to, but not in, the proton beam path. A proton beam therapy system
and an X-ray system combination 2900 is illustrated in FIG. 29. The
proton beam therapy system has a proton beam 268 in a transport system
after the Lamberson extraction magnet 292 of the synchrotron 130. The
proton beam is directed by the scanning/targeting/delivery system 140 to
a tumor 2120 of a patient 2130. The X-ray system 2905 includes an
electron beam source 2805 generating an electron beam 2850. The electron
beam is directed to an X-ray generation source 2848, such as a piece of
tungsten. Preferably, the tungsten X-ray source is located about 1, 2, 3,
5, 10, 15, or 20 millimeters from the proton beam path 268. When the
electron beam 2850 hits the tungsten, X-rays are generated in all
directions. X-rays are blocked with a port 2962 and are selected for an
X-ray beam path 2970. The X-ray beam path 2970 and proton beam path 268
run substantially in parallel as they progress to the tumor 2120. The
distance between the X-ray beam path 2970 and proton beam path 269
preferably diminishes to near zero and/or the X-ray beam path 2970 and
proton beam path 269 overlap by the time they reach the tumor 2120.
Simple geometry shows this to be the case given the long distance, of at
least a meter, between the tungsten and the tumor 2120. The distance is
illustrated as a gap 2980 in FIG. 29. The X-rays are detected at an X-ray
detector 2990, which is used to form an image of the tumor 2120 and/or
position of the patient 2130.

[0289]As a whole, the system generates an X-ray beam that lies in
substantially the same path as the proton therapy beam. The X-ray beam is
generated by striking a tungsten or equivalent material with an electron
beam. The X-ray generation source is located proximate to the proton beam
path. Geometry of the incident electrons, geometry of the X-ray
generation material, and/or geometry of the X-ray beam blocker 262 yield
an X-ray beam that runs either substantially in parallel with the proton
beam or results in an X-ray beam path that starts proximate the proton
beam path an expands to cover and transmit through a tumor
cross-sectional area to strike an X-ray detector array or film allowing
imaging of the tumor from a direction and alignment of the proton therapy
beam. The X-ray image is then used to control the charged particle beam
path to accurately and precisely target the tumor, and/or is used in
system verification and validation.

[0291]Referring now to FIG. 31, a 3-dimensional (3-D) X-ray tomography
system 3100 is presented. In a typical X-ray tomography system, the X-ray
source and detector rotationally translate about a stationary subject. In
the X-ray tomography system described herein, the X-ray source and
detector are stationary and the patient 2130 rotates. The stationary
X-ray source allows a system where the X-ray source 2848 is proximate the
proton therapy beam path 268, as described supra. In addition, the
rotation of the patient 2130 allows the proton dosage to be distributed
around the body, rather than being concentrated on one static entrance
side of the body. Further, the 3-D X-ray tomography system allows for
simultaneous updates of the tumor position relative to body constituents
in real-time during proton therapy treatment of the tumor 2120 in the
patient 2130. The X-ray tomography system is further described, infra.

[0292]In a first step of the X-ray tomography system 3100, the patient
2130 is positioned relative to the X-ray beam path 2970 and proton beam
path 268 using a patient semi-immobilization/placement system, described
infra. After patient 2130 positioning, a series of reference 2-D X-ray
images are collected, on a detector array 2990 or film, of the patient
2130 and tumor 2120 as the subject is rotated about a y-axis 2117. For
example, a series of about 50, 100, 200, or 400 X-ray images of the
patient are collected as the patient is rotated. In a second example, an
X-ray image is collected with each n degrees of rotation of the patient
2130, where n is about 1/2, 1, 2, 3, or 5 degrees of rotation.
Preferably, about 200 images are collected during one full rotation of
the patient through 360 degrees. Subsequently, using the reference 2-D
X-ray images, an algorithm produces a reference 3-D picture of the tumor
2120 relative to the patient's constituent body parts. A tumor 2120
irradiation plan is made using the 3-D picture of the tumor 2120 and the
patient's constituent body parts. Creation of the proton irradiation plan
is optionally performed after the patient has moved from the X-ray
imaging area.

[0293]In a second step, the patient 2130 is repositioned relative to the
X-ray beam path 2970 and proton beam path 268 using the patient
semi-immobilization/placement system. Just prior to implementation of the
proton irradiation plan, a few comparative X-ray images of the patient
2130 and tumor 2120 are collected at a limited number of positions using
the X-ray tomography system 2600 setup. For example, a single X-ray image
is collected with the patient positioned straight on, at angles of
plus/minus forty-five degrees, and/or at angles of plus/minus ninety
degrees relative to the proton beam path 268. The actual orientation of
the patient 2130 relative to the proton beam path 268 is optionally any
orientation. The actual number of comparative X-ray images is also
optionally any number of images, though the preferable number of
comparative X-ray images is about 2 to 5 comparative images. The
comparative X-ray images are compared to the reference X-ray images and
differences are detected. A medical expert or an algorithm determines if
the difference between the reference images and the comparative images is
significant. Based upon the differences, the medical expert or algorithm
determines if: proton treatment should commence, be halted, or adapted in
real-time. For example, if significant differences in the X-ray images
are observed, then the treatment is preferably halted and the process of
collecting a reference 3-D picture of the patient's tumor is reinitiated.
In a second example, if the differences in the X-ray images are observed
to be small, then the proton irradiation plan commences. In a third
example, the algorithm or medical expert can adapt the proton irradiation
plan in real-time to adjust for differences in tumor location resulting
from changes in position of the tumor 2120 in the patient 2130 or from
differences in the patient 2130 placement. In the third example, the
adaptive proton therapy increases patient throughput and enhances
precision and accuracy of proton irradiation of the tumor 2120 relative
to the healthy tissue of the patient 2130.

Patient Immobilization

[0294]Accurate and precise delivery of a proton beam to a tumor of a
patient requires: (1) positioning control of the proton beam and (2)
positioning control of the patient. As described, supra, the proton beam
is controlled using algorithms and magnetic fields to a diameter of about
0.5, 1, or 2 millimeters. This section addresses partial immobilization,
restraint, and/or alignment of the patient to insure the tightly
controlled proton beam efficiently hits a target tumor and not
surrounding healthy tissue as a result of patient movement.

[0295]Herein, an x-, y-, and z-axes coordinate system and rotation axis is
used to describe the orientation of the patient relative to the proton
beam. The z-axis represent travel of the proton beam, such as the depth
of the proton beam into the patient. When looking at the patient down the
z-axis of travel of the proton beam, the x-axis refers to moving left or
right across the patient and the y-axis refers to movement up or down the
patient. A first rotation axis is rotation of the patient about the
y-axis and is referred to herein as a rotation axis, bottom unit 2112
rotation axis, or y-axis of rotation 2117. In addition, tilt is rotation
about the x-axis, yaw is rotation about the y-axis, and roll is rotation
about the z-axis. In this coordinate system, the proton beam path 269
optionally runs in any direction. As an illustrative matter, the proton
beam path running through a treatment room is described as running
horizontally through the treatment room.

[0296]In this section, three examples of positioning systems are provided:
(1) a semi-vertical partial immobilization system 3200; (2) a sitting
partial immobilization system 3300; and (3) a laying position 3400.
Elements described for one immobilization system apply to other
immobilization systems with small changes. For example, a headrest, a
head support, or head restraint will adjust along one axis for a reclined
position, along a second axis for a seated position, and along a third
axis for a laying position. However, the headrest itself is similar for
each immobilization position.

Vertical Patient Positioning/Immobilization

[0297]Referring now to FIG. 32, the semi-vertical patient positioning
system 3200 is preferably used in conjunction with proton therapy of
tumors in the torso. The patient positioning and/or immobilization system
controls and/or restricts movement of the patient during proton beam
therapy. In a first partial immobilization embodiment, the patient is
positioned in a semi-vertical position in a proton beam therapy system.
As illustrated, the patient is reclining at an angle alpha, α,
about 45 degrees off of the y-axis as defined by an axis running from
head to foot of the patient. More generally, the patient is optionally
completely standing in a vertical position of zero degrees off the of
y-axis or is in a semi-vertical position alpha that is reclined about 5,
10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65 degrees off of the
y-axis toward the z-axis.

[0298]Patient positioning constraints 3215 that are used to maintain the
patient in a treatment position, include one or more of: a seat support
3220, a back support 3230, a head support 3240, an arm support 3250, a
knee support 3260, and a foot support 3270. The constraints are
optionally and independently rigid or semi-rigid. Examples of a
semi-rigid material include a high or low density foam or a visco-elastic
foam. For example the foot support is preferably rigid and the back
support is preferably semi-rigid, such as a high density foam material.
One or more of the positioning constraints 3215 are movable and/or under
computer control for rapid positioning and/or immobilization of the
patient. For example, the seat support 3220 is adjustable along a seat
adjustment axis 3222, which is preferably the y-axis; the back support
3230 is adjustable along a back support axis 3232, which is preferably
dominated by z-axis movement with a y-axis element; the head support 3240
is adjustable along a head support axis 3242, which is preferably
dominated by z-axis movement with a y-axis element; the arm support 3250
is adjustable along an arm support axis 3252, which is preferably
dominated by z-axis movement with a y-axis element; the knee support 3260
is adjustable along a knee support axis 3262, which is preferably
dominated by z-axis movement with a y-axis element; and the foot support
3270 is adjustable along a foot support axis 3272, which is preferably
dominated by y-axis movement with a z-axis element.

[0299]If the patient is not facing the incoming proton beam, then the
description of movements of support elements along the axes change, but
the immobilization elements are the same.

[0300]An optional camera 3280 is used with the patient immobilization
system. The camera views the patient/subject 2130 creating a video image.
The image is provided to one or more operators of the charged particle
beam system and allows the operators a safety mechanism for determining
if the subject has moved or desires to terminate the proton therapy
treatment procedure. Based on the video image, the operators optionally
suspend or terminate the proton therapy procedure. For example, if the
operator observes via the video image that the subject is moving, then
the operator has the option to terminate or suspend the proton therapy
procedure.

[0301]An optional video display or display monitor 3290 is provided to the
patient. The video display optionally presents to the patient any of:
operator instructions, system instructions, status of treatment, or
entertainment.

[0303]Respiration control is optionally performed by using the video
display. As the patient breathes, internal and external structures of the
body move in both absolute terms and in relative terms. For example, the
outside of the chest cavity and internal organs both have absolute moves
with a breath. In addition, the relative position of an internal organ
relative to another body component, such as an outer region of the body,
a bone, support structure, or another organ, moves with each breath.
Hence, for more accurate and precise tumor targeting, the proton beam is
preferably delivered at a point in time where the position of the
internal structure or tumor is well defined, such as at the bottom or top
of each breath. The video display is used to help coordinate the proton
beam delivery with the patient's respiration cycle. For example, the
video display optionally displays to the patient a command, such as a
hold breath statement, a breathe statement, a countdown indicating when a
breath will next need to be held, or a countdown until breathing may
resume.

Sitting Patient Positioning/Immobilization

[0304]In a second partial immobilization embodiment, the patient is
partially restrained in a seated position 3300. The sitting restraint
system uses support structures similar to the support structures in the
semi-vertical positioning system, described supra, with an exception that
the seat support is replaced by a chair and the knee support is not
required. The seated restraint system generally retains the adjustable
support, rotation about the y-axis, camera, video, and breadth control
parameters described in the semi-vertical embodiment, described supra.

[0305]Referring now to FIG. 33, a particular example of a sitting patient
semi-immobilization system 3300 is provided. The sitting system is
preferably used for treatment of head and/or neck tumors. As illustrated,
the patient is positioned in a seated position on a chair 3310 for
particle therapy. The patient is further immobilized using any of the:
the head support 3240, the back support 3230, the hand support 3250, the
knee support 3260, and the foot support 3270. The supports 3220, 3230,
3240, 3250, 3260, 3270 preferably have respective axes of adjustment
3222, 3232, 3242, 3252, 3262, 3272 as illustrated. The chair 3310 is
either readily removed to allow for use of a different patient constraint
system or adapts under computer control to a new patient position, such
as the semi-vertical system.

Laying Patient Positioning/Immobilization

[0306]In a third partial immobilization embodiment, the patient is
partially restrained in a laying position. The laying restraint system
3400 has support structures that are similar to the support structures
used in the sitting positioning system 3300 and semi-vertical positioning
system 3200, described supra. In the laying position, optional restraint,
support, or partial immobilization elements include one or more of: the
head support 3240 and the back support, hip, and shoulder 3230 support.
The supports preferably have respective axes of adjustment that are
rotated as appropriate for a laying position of the patient. The laying
position restraint system generally retains the adjustable supports,
rotation about the y-axis, camera, video, and breadth control parameters
described in the semi-vertical embodiment, described supra.

[0307]If the patient is very sick, such as the patient has trouble
standing for a period of about one to three minutes required for
treatment, then being in a partially supported system can result in some
movement of the patient due to muscle strain. In this and similar
situations, treatment of a patient in a laying position on a support
table 3420 is preferentially used. The support table has a horizontal
platform to support the bulk of the weight of the patient. Preferably,
the horizontal platform is detachable from a treatment platform. In a
laying positioning system 3400, the patient is positioned on a platform
3410, which has a substantially horizontal portion for supporting the
weight of the body in a horizontal position. Optional hand grips are
used, described infra. In one embodiment, the platform 3410 affixes
relative to the table 3420 using a mechanical stop or lock element 3430
and matching key element 3435 and/or the patient 2130 is aligned or
positioned relative to a placement element 3460.

[0308]Additionally, upper leg support 3444, lower leg support 3440, and/or
arm support 3450 elements are optionally added to raise, respectively, an
arm or leg out of the proton beam path 269 for treatment of a tumor in
the torso or to move an arm or leg into the proton beam path 269 for
treatment of a tumor in the arm or leg. This increases proton delivery
efficiency, as described supra. The leg supports 3440, 3444 and arm
support 3450 are each optionally adjustable along support axes or arcs
3442, 3446, 3452. One or more leg support elements are optionally
adjustable along an arc to position the leg into the proton beam path 269
or to remove the leg from the proton beam path 269, as described infra.
An arm support element is preferably adjustable along at least one arm
adjustment axis or along an arc to position the arm into the proton beam
path 269 or to remove the arm from the proton beam path 269, as described
infra.

[0309]Preferably, the patient is positioned on the platform 3410 in an
area or room outside of the proton beam path 268 and is wheeled or slid
into the treatment room or proton beam path area. For example, the
patient is wheeled into the treatment room on a gurney where the top of
the gurney, which is the platform, detaches and is positioned onto a
table. The platform is preferably lifted onto the table or slid onto the
table so that the gurney or bed need not be lifted onto the table.

[0310]The semi-vertical patient positioning system 3200 and sitting
patient positioning system 3300 are preferentially used to treatment of
tumors in the head or torso due to efficiency. The semi-vertical patient
positioning system 3200, sitting patient positioning system 3300, and
laying patient positioning system 3400 are all usable for treatment of
tumors in the patient's limbs.

Support System Elements

[0311]Positioning constraints 3215 include all elements used to position
the patient, such as those described in the semi-vertical positioning
system 3200, sitting positioning system 3300, and laying positioning
system 3400. Preferably, positioning constraints or support system
elements are aligned in positions that do not impede or overlap the
proton beam path 269. However, in some instances the positioning
constraints are in the proton beam path 269 during at least part of the
time of treatment of the patient. For instance, a positioning constraint
element may reside in the proton beam path 269 during part of a time
period where the patient is rotated about the y-axis during treatment. In
cases or time periods that the positioning constraints or support system
elements are in the proton beam path, then an upward adjustment of proton
beam energy is preferably applied that increases the proton beam energy
to offset the positioning constraint element impedance of the proton
beam. This time period and energy is a function of rotational orientation
of the patient. In one case, the proton beam energy is increased by a
separate measure of the positioning constraint element impedance
determined during a reference scan of the positioning constraint system
element or set of reference scans of the positioning constraint element
as a function of rotation about the y-axis.

[0312]For clarity, the positioning constraints 3215 or support system
elements are herein described relative to the semi-vertical positioning
system 3200; however, the positioning elements and descriptive x-, y-,
and z-axes are adjustable to fit any coordinate system, to the sitting
positioning system 3300, or the laying positioning system 3400.

[0313]An example of a head support system is described to support, align,
and/or restrict movement of a human head. The head support system
preferably has several head support elements including any of: a back of
head support, a right of head alignment element, and a left of head
alignment element. The back of head support element is preferably curved
to fit the head and is optionally adjustable along a head support axis,
such as along the z-axis. Further, the head supports, like the other
patient positioning constraints, is preferably made of a semi-rigid
material, such as a low or high density foam, and has an optional
covering, such as a plastic or leather. The right of head alignment
element and left of head alignment elements or head alignment elements,
are primarily used to semi-constrain movement of the head or to fully
immobilize the head. The head alignment elements are preferably padded
and flat, but optionally have a radius of curvature to fit the side of
the head. The right and left head alignment elements are preferably
respectively movable along translation axes to make contact with the
sides of the head. Restricted movement of the head during proton therapy
is important when targeting and treating tumors in the head or neck. The
head alignment elements and the back of head support element combine to
restrict tilt, rotation or yaw, roll and/or position of the head in the
x-, y-, z-axes coordinate system.

[0314]Referring now to FIG. 35 another example of a head support system
3500 is described for positioning and/or restricting movement of a human
head 2102 during proton therapy of a solid tumor in the head or neck. In
this system, the head is restrained using 1, 2, 3, 4, or more straps or
belts, which are preferably connected or replaceably connected to a back
of head support element 3510. In the example illustrated, a first strap
3520 pulls or positions the forehead to the head support element 3510,
such as by running predominantly along the z-axis. Preferably a second
strap 3530 works in conjunction with the first strap 3520 to prevent the
head from undergoing tilt, yaw, roll or moving in terms of translational
movement on the x-, y-, and z-axes coordinate system. The second strap
3530 is preferably attached or replaceable attached to the first strap
3520 at or about: (1) a forehead position 3532; (2) at a position on one
or both sides of the head 3534; and/or (3) a position at or about the
support element 3510. A third strap 3540 preferably orientates the chin
of the subject relative to the support element 3510 by running dominantly
along the z-axis. A fourth strap 3550 preferably runs along a
predominantly y- and z-axes to hold the chin relative to the head support
element 3510 and/or proton beam path. The third 3540 strap preferably is
attached to or is replaceably attached to the fourth strap 3550 during
use at or about the patient's chin position 3542. The second strap 3530
optionally connects 3536 to the fourth strap 3550 at or about the support
element 3510. The four straps 3520, 3530, 3540, 3550 are illustrative in
pathway and interconnection. Any of the straps optionally hold the head
along different paths around the head and connect to each other in
separate fashion. Naturally, a given strap preferably runs around the
head and not just on one side of the head. Any of the straps 3520, 3530,
3540, and 3550 are optionally used independently or in combinations and
permutations with the other straps. The straps are optionally indirectly
connected to each other via a support element, such as the head support
element 3510. The straps are optionally attached to the head support
element 3510 using hook and loop technology, a buckle, or fastener.
Generally, the straps combine to control position, front-to-back movement
of the head, side-to-side movement of the head, tilt, yaw, roll, and/or
translational position of the head.

[0315]The straps are preferably of known impedence to proton transmission
allowing a calculation of peak energy release along the z-axis to be
calculated. For example, adjustment to the Bragg peak energy is made
based on the slowing tendency of the straps to proton transport.

[0316]Referring now to FIG. 36, still another example of a head support
system 3240 is described. The head support 3240 is preferably curved to
fit a standard or child sized head. The head support 3240 is optionally
adjustable along a head support axis 3242. Further, the head supports,
like the other patient positioning constraints, is preferably made of a
semi-rigid material, such as a low or high density foam, and has an
optional covering, such as a plastic or leather.

[0317]Elements of the above described head support, head positioning, and
head immobilization systems are optionally used separately or in
combination.

[0318]Still referring to FIG. 36, an example of the arm support 3250 is
further described. The arm support preferably has a left hand grip 3610
and a right hand grip 3620 used for aligning the upper body of the
patient 2130 through the action of the patient 2130 gripping the left and
right hand grips 3610, 3620 with the patient's hands 2134. The left and
right hand grips 3610, 3620 are preferably connected to the arm support
3250 that supports the mass of the patient's arms. The left and right
hand grips 3610, 3620 are preferably constructed using a semi-rigid
material. The left and right hand grips 3610, 3620 are optionally molded
to the patient's hands to aid in alignment. The left and right hand grips
optionally have electrodes, as described supra.

Patient Respiration Monitoring

[0319]Preferably, the patient's breathing pattern is monitored. When a
subject or patient 2130 is breathing many portions of the body move with
each breath. For example, when a subject breathes the lungs move as do
relative positions of organs within the body, such as the stomach,
kidneys, liver, chest muscles, skin, heart, and lungs. Generally, most or
all parts of the torso move with each breath. Indeed, the inventors have
recognized that in addition to motion of the torso with each breath,
various motion also exists in the head and limbs with each breath. Motion
is to be considered in delivery of a proton dose to the body as the
protons are preferentially delivered to the tumor and not to surrounding
tissue. Motion thus results in an ambiguity in where the tumor resides
relative to the beam path.

[0320]To partially overcome this concern, protons are preferentially
delivered at the same point in each of a series of respiration cycles.

[0321]Initially a rhythmic pattern of breathing of a subject is
determined. The cycle is observed or measured. For example, an X-ray beam
operator or proton beam operator can observe when a subject is breathing
or is between breaths and can time the delivery of the protons to a given
period of each breath. Alternatively, the subject is told to inhale,
exhale, and/or hold their breath and the protons are delivered during the
commanded time period.

[0322]Preferably, one or more sensors are used to determine the
respiration cycle of the individual. Two examples of a respiration
monitoring system are provided: (1) a thermal monitoring system and (2) a
force monitoring system.

[0323]Referring again to FIG. 35, a first example of the thermal
respiration monitoring system is provided. In the thermal respiration
monitoring system, a sensor is placed by the nose and/or mouth of the
patient. As the jaw of the patient is optionally constrained, as
described supra, the thermal respiration monitoring system is preferably
placed by the patient's nose exhalation path. To avoid steric
interference of the thermal sensor system components with proton therapy,
the thermal respiration monitoring system is preferably used when
treating a tumor not located in the head or neck, such as a when treating
a tumor in the torso or limbs. In the thermal monitoring system, a first
thermal resistor 3570 is used to monitor the patient's respiration cycle
and/or location in the patient's respiration cycle. Preferably, the first
thermal resistor 3570 is placed by the patient's nose, such that the
patient exhaling through their nose onto the first thermal resistor 3570
warms the first thermal resistor 3570 indicating an exhale. Preferably, a
second thermal resistor 3560 operates as an environmental temperature
sensor. The second thermal resistor 3560 is preferably placed out of the
exhalation path of the patient but in the same local room environment as
the first thermal resistor 3570. Generated signal, such as current from
the thermal resistors 3570, 3560, is preferably converted to voltage and
communicated with the main controller 110 or a sub-controller of the main
controller. Preferably, the second thermal resistor 3560 is used to
adjust for the environmental temperature fluctuation that is part of a
signal of the first thermal resistor 3570, such as by calculating a
difference between the values of the thermal resistors 3570, 3560 to
yield a more accurate reading of the patient's respiration cycle.

[0324]Referring again to FIG. 33, a second example of a monitoring system
is provided. In an example of a force respiration monitoring system, a
sensor is placed by the torso. To avoid steric interference of the force
sensor system components with proton therapy, the force respiration
monitoring system is preferably used when treating a tumor located in the
head, neck, or limbs. In the force monitoring system, a belt or strap
3350 is placed around an area of the patient's torso that expands and
contracts with each respiration cycle of the patient. The belt 3350 is
preferably tight about the patient's chest and is flexible. A force meter
3352 is attached to the belt and senses the patients breathing pattern.
The forces applied to the force meter 3352 correlate with periods of the
respiration cycle. The signals from the force meter 3352 are preferably
communicated with the main controller 110 or a sub-controller of the main
controller.

Respiration Control

[0325]Referring now to FIG. 37, a patient is positioned 3710 and once the
rhythmic pattern of the subject's breathing or respiration cycle is
determined 3720, a signal is optionally delivered to the patient, such as
via the display monitor 3290, to more precisely control the breathing
frequency 3730. For example, the display screen 3290 is placed in front
of the patient and a message or signal is transmitted to the display
screen 3290 directing the subject when to hold their breath and when to
breathe. Typically, a respiration control module uses input from one or
more of the breathing sensors. For example, the input is used to
determine when the next breath exhale is to complete. At the bottom of
the breath, the control module displays a hold breath signal to the
subject, such as on a monitor, via an oral signal, digitized and
automatically generated voice command, or via a visual control signal.
Preferably, a display monitor 3290 is positioned in front of the subject
and the display monitor displays breathing commands to the subject.
Typically, the subject is directed to hold their breath for a short
period of time, such as about 1/2, 1, 2, 3, 5, or 10 seconds. The period
of time the breath is held is preferably synchronized to the delivery
time of the proton beam to the tumor, which is about 1/2, 1, 2, or 3
seconds. While delivery of the protons at the bottom of the breath is
preferred, protons are optionally delivered at any point in the
respiration cycle, such as upon full inhalation. Delivery at the top of
the breath or when the patient is directed to inhale deeply and hold
their breath by the respiration control module is optionally performed as
at the top of the breath the chest cavity is largest and for some tumors
the distance between the tumor and surrounding tissue is maximized or the
surrounding tissue is rarefied as a result of the increased volume.
Hence, protons hitting surrounding tissue is minimized. Optionally, the
display screen tells the subject when they are about to be asked to hold
their breath, such as with a 3, 2, 1, second countdown so that the
subject is aware of the task they are about to be asked to perform.

X-Ray Synchronization with Patient Respiration

[0326]In one embodiment, X-ray images are collected in synchronization
with patient respiration. The synchronization enhances X-ray image
clarity by removing position ambiguity due to the relative movement of
body constituents during a patient respiration cycle.

[0327]In a second embodiment, an X-ray system is orientated to provide
X-ray images of a patient in the same orientation as viewed by a proton
therapy beam, is synchronized with patient respiration, is operable on a
patient positioned for proton therapy, and does not interfere with a
proton beam treatment path. Preferably, the synchronized system is used
in conjunction with a negative ion beam source, synchrotron, and/or
targeting method and apparatus to provide an X-ray timed with patient
respiration. Preferably, X-ray images are collected immediately prior to
and/or concurrently with particle beam therapy irradiation to ensure
targeted and controlled delivery of energy relative to a patient position
resulting in efficient, precise, and/or accurate in-vivo treatment of a
solid cancerous tumor with minimization of damage to surrounding healthy
tissue.

[0328]An X-ray delivery control algorithm is used to synchronize delivery
of the X-rays to the patient 2130 within a given period of each breath,
such as at the top or bottom of a breath, and/or when the subject is
holding their breath. For clarity of combined X-ray images, the patient
is preferably both accurately positioned and precisely aligned relative
to the X-ray beam path 2970. The X-ray delivery control algorithm is
preferably integrated with the respiration control module. Thus, the
X-ray delivery control algorithm knows when the subject is breathing,
where in the respiration cycle the subject is, and/or when the subject is
holding their breath. In this manner, the X-ray delivery control
algorithm delivers X-rays at a selected period of the respiration cycle.
Accuracy and precision of patient alignment allow for (1) more accurate
and precise location of the tumor 2120 relative to other body
constituents and (2) more accurate and precise combination of X-rays in
generation of a 3-dimensional X-ray image of the patient 2130 and tumor
2120.

[0329]Referring again to FIG. 37, an example of generating an X-ray image
of the patient 2130 and tumor 2120 using the X-ray generation device 2800
or 3-dimensional X-ray generation device 2800 as a known function of time
of the patient's respiration cycle is provided. In one embodiment, as a
first step the main controller 110 instructs, monitors, and/or is
informed of patient positioning 3710. In a first example of patient
positioning 3710, the automated patient positioning system, described
supra, under main controller 110 control, is used to align the patient
2130 relative to the X-ray beam path 2970. In a second example of patient
positioning, the main controller 110 is told via sensors or human input
that the patient 2130 is aligned. In a second step, patient respiration
is then monitored 3720, as described infra. As a first example of
breathing monitoring, an X-ray is collected 3740 at a known point in the
patient respiration cycle. In a second example of breathing monitoring,
the patient's respiration cycle is first controlled in a third step of
controlling patient respiration 3730 and then as a fourth step an X-ray
is collected 3740 at a controlled point in the patient respiration cycle.
Preferably, the cycle of patient positioning 3710, patient respiration
monitoring 3720, patient respiration control 3730, and collecting an
X-ray 3740 is repeated with different patient positions. For example, the
patient 2130 is rotated about an axis 2117 and X-rays are collected as a
function of the rotation. In a fifth step, a 3-dimensional X-ray image
3745 is generated of the patient 2130, tumor 2120, and body constituents
about the tumor using the collected X-ray images, such as with the
3-dimensional X-ray generation device 2800, described supra. The patient
respiration monitoring and control steps are further described, infra.

Proton Beam Therapy Synchronization with Respiration

[0330]In one embodiment, charged particle therapy and preferably
multi-field proton therapy is coordinated and synchronized with patient
respiration via use of the respiration feedback sensors, described supra,
used to monitor and/or control patient respiration. Preferably, the
charged particle therapy is performed on a patient in a partially
immobilized and repositionable position and the proton delivery to the
tumor 2120 is timed to patient respiration via control of charged
particle beam injection, acceleration, extraction, and/or targeting
methods and apparatus. The synchronization enhances proton delivery
accuracy by removing position ambiguity due to the relative movement of
body constituents during a patient respiration cycle.

[0331]In a second embodiment, the X-ray system, described supra, is used
to provide X-ray images of a patient in the same orientation as viewed by
a proton therapy beam and both the X-ray system and the proton therapy
beam are synchronized with patient respiration. Preferably, the
synchronized system is used in conjunction with the negative ion beam
source, synchrotron, and/or targeting method and apparatus to provide an
X-ray timed with patient respiration where the X-ray is collected
immediately prior to and/or concurrently with particle beam therapy
irradiation to ensure targeted and controlled delivery of energy relative
to a patient position resulting in efficient, precise, and/or accurate
treatment of a solid cancerous tumor with minimization of damage to
surrounding healthy tissue in a patient using the proton beam position
verification system.

[0332]A proton delivery control algorithm is used to synchronize delivery
of the protons to the tumor within a given period of each breath, such as
at the top of a breath, at the bottom of a breath, and/or when the
subject is holding their breath. The proton delivery control algorithm is
preferably integrated with the respiration control module. Thus, the
proton delivery control algorithm knows when the subject is breathing,
where in the respiration cycle the subject is, and/or when the subject is
holding their breath. The proton delivery control algorithm controls when
protons are injected and/or inflected into the synchrotron, when an RF
signal is applied to induce an oscillation, as described supra, and when
a DC voltage is applied to extract protons from the synchrotron, as
described supra. Typically, the proton delivery control algorithm
initiates proton inflection and subsequent RF induced oscillation before
the subject is directed to hold their breath or before the identified
period of the respiration cycle selected for a proton delivery time. In
this manner, the proton delivery control algorithm delivers protons at a
selected period of the respiration cycle by simultaneously or nearly
simultaneously delivering the high DC voltage to the second pair of
plates, described supra, which results in extraction of the protons from
the synchrotron and subsequent delivery to the subject at the selected
time point. Since the period of acceleration of protons in the
synchrotron is constant or known for a desired energy level of the proton
beam, the proton delivery control algorithm is used to set an AC RF
signal that matches the respiration cycle or directed respiration cycle
of the subject.

[0333]The above described charged particle therapy elements are combined
in combinations and/or permutations in developing and implementing a
tumor treatment plan, described infra.

Developing and Implementing a Tumor Irradiation Plan

[0334]A series of steps are performed to design and execute a radiation
treatment plan for treating a tumor 2120 in a patient 2130. The steps
include one or more of: [0335]positioning and immobilizing the patient;
[0336]recording the patient position; [0337]monitoring patient
respiration; [0338]controlling patient respiration; [0339]collecting
multi-field images of the patient to determine tumor location relative to
body constituents; [0340]developing a radiation treatment plan;
[0341]repositioning the patient; [0342]verifying tumor location; and
[0343]irradiating the tumor.

[0344]In this section, an overview of developing the irradiation plan and
subsequent implementation of the irradiation plan is initially presented,
the individual steps are further described, and a more detailed example
of the process is then described.

[0345]Referring now to FIG. 38, an overview of a system for development of
an irradiation plan and subsequent implementation of the irradiation plan
3800 is provided. Preferably, all elements of the positioning,
respiration monitoring, imaging, and tumor irradiation system 3800 are
under main controller 110 control.

[0346]Initially, the tumor containing volume of the patient 2130 is
positioned and immobilized 3710 in a controlled and reproducible
position. The process of positioning and immobilizing 3710 the patient
2310 is preferably iterated 3812 until the position is accepted. The
position is preferably digitally recorded 3815 and is later used in a
step of computer controlled repositioning of the patient 3817 in the
minutes or seconds prior to implementation of the irradiation element
3870 of the tumor treatment plan. The process of positioning the patient
in a reproducible fashion and reproducibly aligning the patient 2310 to
the controlled position is further described, infra.

[0347]Subsequent to patient positioning 3710, the steps of monitoring 3720
and preferably controlling 3730 the respiration cycle of the patient 2130
are preferably performed to yield more precise positioning of the tumor
2120 relative to other body constituents, as described supra. Multi-field
images of the tumor are then collected 3840 in the controlled,
immobilized, and reproducible position. For example, multi-field X-ray
images of the tumor 2120 are collected using the X-ray source proximate
the proton beam path, as described supra. The multi-field images are
optionally from three or more positions and/or are collected while the
patient is rotated, as described supra.

[0348]At this point the patient 2130 is either maintained in the treatment
position or is allowed to move from the controlled treatment position
while an oncologist processes the multi-field images 3845 and generates a
tumor treatment plan 3850 using the multi-field images. Optionally, the
tumor irradiation plan is implemented 3870 at this point in time.

[0349]Typically, in a subsequent treatment center visit, the patient 2130
is repositioned 3817. Preferably, the patient's respiration cycle is
again monitored 3722 and/or controlled 3732, such as via use of the
thermal monitoring respiration sensors, force monitoring respiration
sensor, and/or via commands sent to the display monitor 3290, described
supra. Once repositioned, verification images are collected 3860, such as
X-ray location verification images from 1, 2, or 3 directions. For
example, verification images are collected with the patient facing the
proton beam and at rotation angles of 90, 180, and 270 degrees from this
position. At this point, comparing the verification images to the
original multi-field images used in generating the treatment plan, the
algorithm or preferably the oncologist determines if the tumor 2120 is
sufficiently repositioned 3865 relative to other body parts to allow for
initiation of tumor irradiation using the charged particle beam.
Essentially, the step of accepting the final position of the patient 3865
is a safety feature used to verify that that the tumor 2120 in the
patient 2130 has not shifted or grown beyond set specifications. At this
point the charged particle beam therapy commences 3870. Preferably the
patient's respiration is monitored 3724 and/or controlled 3734, as
described supra, prior to commencement of the charged particle beam
treatment 3870.

[0350]Optionally, simultaneous X-ray imaging 3890 of the tumor 2120 is
performed during the multi-field proton beam irradiation procedure and
the main controller 110 uses the X-ray images to adapt the radiation
treatment plan in real-time to account for small variations in movement
of the tumor 2120 within the patient 2130.

[0351]Herein the step of monitoring 3720, 3722, 3724 and controlling 3730,
3732, 3734 the patient's respiration is optional, but preferred. The
steps of monitoring and controlling the patient's respiration are
performed before and/or during the multi-filed imaging 3840, position
verification 3860, and/or tumor irradiation 3870 steps.

[0353]One or more of the patient positioning unit components and/or one of
more of the patient positioning constraints are preferably under computer
control. For example, the computer records or controls the position of
the patient positioning elements 3215, such as via recording a series of
motor positions connected to drives that move the patient positioning
elements 3215. For example, the patient is initially positioned 3710 and
constrained by the patient positioning constraints 3215. The position of
each of the patient positioning constraints is recorded and saved by the
main controller 110, by a sub-controller of the main controller 110, or
by a separate computer controller. Then, imaging systems are used to
locate the tumor 2120 in the patient 2130 while the patient is in the
controlled position of final treatment. Preferably, when the patient is
in the controlled position, multi-field imaging is performed, as
described herein. The imaging system 170 includes one or more of: MRI's,
X-rays, CT's, proton beam tomography, and the like. Time optionally
passes at this point while images from the imaging system 170 are
analyzed and a proton therapy treatment plan is devised. The patient
optionally exits the constraint system during this time period, which may
be minutes, hours, or days. Upon, and preferably after, return of the
patient and initial patient placement into the patient positioning unit,
the computer returns the patient positioning constraints to the recorded
positions. This system allows for rapid repositioning of the patient to
the position used during imaging and development of the multi-field
charged particle irradiation treatment plan, which minimizes setup time
of patient positioning and maximizes time that the charged particle beam
system 100 is used for cancer treatment.

Reproducing Patient Positioning and Immobilization

[0354]In one embodiment, using a patient positioning and immobilization
system 3800, a region of the patient 2130 about the tumor 2120 is
reproducibly positioned and immobilized, such as with the motorized
patient translation and rotation positioning system 2110 and/or with the
patient positioning constraints 3215. For example, one of the above
described positioning systems, such as (1) the semi-vertical partial
immobilization system 3200; (2) the sitting partial immobilization system
3300; or (3) the laying position system 3400 is used in combination with
the patient translation and rotation system 2110 to position the tumor
2120 of the patient 2130 relative to the proton beam path 268.
Preferably, the position and immobilization system 3800 controls position
of the tumor 2120 relative to the proton beam path 268, immobilizes
position of the tumor 2120, and facilitates repositioning the tumor 2120
relative to the proton beam path 268 after the patient 2130 has moved
away from the proton beam path 268, such as during development of the
irradiation treatment plan 3845.

[0355]Preferably, the tumor 2120 of the patient 2130 is positioned in
terms of 3-D location and in terms of orientation attitude. Herein, 3-D
location is defined in terms of the x-, y-, and z-axes and orientation
attitude is the state of pitch, yaw, and roll. Roll is rotation of a
plane about the z-axis, pitch is rotation of a plane about the x-axis,
and yaw is the rotation of a plane about the y-axis. Tilt is used to
describe both roll and pitch. Preferably, the positioning and
immobilization system 3800 controls the tumor 2120 location relative to
the proton beam path 268 in terms of at least three of and preferably in
terms of four, five, or six of: pitch, yaw, roll, x-axis location, y-axis
location, and z-axis location.

Chair

[0356]The patient positioning and immobilization system 3800 is further
described using a chair positioning example. For clarity, a case of
positioning and immobilizing a tumor in a shoulder is described using
chair positioning. Using the semi-vertical immobilization system 3200,
the patient is generally positioned using the seat support 3220, knee
support 3260, and/or foot support 3270. To further position the shoulder,
a motor in the back support 3230 pushes against the torso of the patient.
Additional arm support 3250 motors align the arm, such as by pushing with
a first force in one direction against the elbow of the patient and the
wrist of the patient is positioned using a second force in a counter
direction. This restricts movement of the arm, which helps to position
the shoulder. Optionally, the head support is positioned to further
restrict movement of the shoulder by applying tension to the neck.
Combined, the patient positioning constraints 3215 control position of
the tumor 2120 of the patient 2130 in at least three dimensions and
preferably control position of the tumor 2120 in terms of all of yaw,
roll, and pitch movement as well as in terms of x-, y-, and z-axis
position. For instance, the patient positioning constraints position the
tumor 2120 and restricts movement of the tumor, such as by preventing
patient slumping. Optionally, sensors in one or more of the patient
positioning constraints 3215 record an applied force. In one case, the
seat support senses weight and applies a force to support a fraction of
the patient's weight, such as about 50, 60, 70, or 80 percent of the
patient's weight. In a second case, a force applied to the neck, arm,
and/or leg is recorded.

[0357]Generally, the patient positioning and immobilization system 3800
removes movement degrees of freedom from the patient 2130 to accurately
and precisely position and control the position of the tumor 2120
relative to the X-ray beam path 2970, proton beam path 268, and/or an
imaging beam path. Further, once the degrees of freedom are removed, the
motor positions for each of the patient positioning constraints are
recorded and communicated digitally to the main controller 110. Once the
patient moves from the immobilization system 3800, such as when the
irradiation treatment plan is generated 3850, the patient 2130 must be
accurately repositioned before the irradiation plan is implemented. To
accomplish this, the patient 2130 sits generally in the positioning
device, such as the chair, and the main controller sends the motor
position signals and optionally the applied forces back to motors
controlling each of the patient positioning constraints 3215 and each of
the patient positioning constraints 3215 are automatically moved back to
their respective recorded positions. Hence, re-positioning and
re-immobilizing the patient 2130 is accomplished from a time of sitting
to fully controlled position in less than about 10, 30, 60, or 120
seconds.

[0358]Using the computer controlled and automated patient positioning
system, the patient is re-positioned in the positioning and
immobilization system 3800 using the recalled patient positioning
constraint 3215 motor positions; the patient 2130 is translated and
rotated using the patient translation and rotation system 2120 relative
to the proton beam 268; and the proton beam 268 is scanned to its
momentary beam position 269 by the main controller 110, which follows the
generated irradiation treatment plan 3850.

[0359]Although the invention has been described herein with reference to
certain preferred embodiments, one skilled in the art will readily
appreciate that other applications may be substituted for those set forth
herein without departing from the spirit and scope of the present
invention. Accordingly, the invention should only be limited by the
Claims included below.